For me Tears of the False God was one of the few I had a chance to play and was very happy with the epic scale of the architecture/layout and the open-ended exploration-based style of the gameplay. 

Probably not going to restrict it to just 5 for this. This is in no particular order either.

I remember being impressed with sm207_hcm, partly because it was made in a weekend and partly because it's a fun layout with challenging combat and some nice secrets. To be honest, any pack with a Mazu map is worth a download.

jokejam_markie and jokejam_nolcoz I think are worth mentioning. cgl_q too (also by Nolcoz). Quake custom maps tend to be fairly serious, so it's nice to see this crazy shit, not only because it's different but also really funny. There's been a lot of other good humour and weirdness this past year too.

Coppertone Summer Jam had some really nice maps. ctsj_jcr, ctsj_juz and ctsj_markie particularly stand out in my mind for ambition, gameplay and visuals.

zigisp1 (A Verdant Dawn by Zigi) was beautiful and great to explore with 29 secrets. Really fun too. I made a fairly long post on that map's release thread already.

I won't say much about Dwell because I'm biased, but d1m8 (Prescience Overload by Mazu) and d1m9 (Vestigial by JCR) are two of my favourites of the year.

Obviously both of the new maps included with Arcane Dimensions 1.8 are excellent. I think something would be very wrong if they weren't.

From Epochs of Enmity, my favourite maps were eoem4 (the Augur's Mold by Rhoq), eoem6 (Knavel Orange by Fairweather) and eoem9 (Terrorcotta by Markie).

And as is now a tradition, we ended the year with an amazing Bal xmasjam map. It's worth stating too that Bal had a pretty good output last year. 5 releases according to Quaddicted.

There were other maps which I played and enjoyed last year, but those were my favourites, and it's already more than you asked for.

Also, special shout-out to Greenwood for releasing 26 maps in 2020. That's some insane dedication. 

My favs:

Tears of the False God - Bal
Oxyblack Fortress - Heresy
Terrorcotta - Markie Music
Grim Gallows - Markie Music
Within the Flayed Kingdom - Markie Music
Prescience Overload - Mazu
Candles of the Damned - Comrade Beep
Arrivée de L'étranger - Fairweather
Vestigial - JCR
A Verdant Dawn - zigi 

Oops, I forgot about XMAS JAM 2020, so would like to add:

Nuclear Winter Is Coming - Heresy 

This year is a fucking tough one. Too much quality released this year. Feels like I should write a 2020 retrospective just to get everything out of my system, but here's a good set of 5 in no particular order (You want me to pick out of these first two? you're out of your mind!)

1. Terrorcotta by Markie (eoem9)
When I constantly think about what my favorite map was this year, I cannot get this one out of my head. It's a constant replay for me, every encounter has immense creativity and fun, and the visuals are Quake at it's best. I love Backsteingotik, anyone will tell you, but this is the only map that tops that aesthetic.
It's not style over substance either, one of the best elements is the humor of the map. It doesn't try and take itself too seriously, constantly throwing curve-balls at you in the form of a silly spawn encounter, a 100 monster quad-tinged bloodbath, zombies raining from the sky, and a goddamn fully-working stealth section in Quake with multiple different traps all with their own humor or interest attached.
There's no doubt many of these ideas have been tried before, but nothing comes close to the execution here. Markie has improved so much since the beginning of 2020 that it's hard to even think of him as a newcomer. This guy came from not even knowing a 3D editing program to making some of the highest quality levels this game will ever see. Play this.

2. Tears of the False God by Bal (ad_tears)
It's difficult to understand how AD can top itself anymore. Almost every level included has had a profound impact on the community and it's perception of quality, constantly moving the bar up to prohibitive levels only to watch it get smashed next time an update rolls around.
These might be famous last words, but Tears feels like the logical end goal to such an evolution. The map takes advantage of everything the community has build so far, entirely new texture sets, new compiler technology, model-to-map conversion, lighting upgrades, and gameplay opportunities.
To say that the map is simply a spectacle or a feat would be selling it short, though, as it feels like it breaks new ground in the gameplay department as well. Less of a focused, authored experience than something like Terrorcotta, Tears shows that non-linearity in Quake is alive and well, and exploration and gameplay can mix when handled with a careful hand, and your exploration is always rewarded drastically like any good adventure style game would. Powerups, items, even permanent upgrades to your character can be found in hidden nooks and make reaching the collectathon slaughtersecret a fucking treat. A masterclass in taking Quake and making it what you want it to be, to stellar effect.

3. The C.G.L Project by Nolcoz (cgl_q)
If there's something I think many cannot fault Nolcoz for, it is for his creative output. The man doesn't care to constantly create a stock-standard experience, every time he pens a bsp the community comes out on the other end just that little bit more interesting, and there's gotta be some intrinsic value in that.
That being said, I would definitely be selling him short if I didn't bring up C.G.L Project, or talk about how much fun I had playing it. It might not be traditional, it might not even really be Quake, but the experience of playing this map blind is worth so much more than that. The music, the set-pieces, just how overwhelming it all is until that final encounter happens... there's *literally* nothing else like it in Quake.
I'm finding it really hard to talk about this without spoilers, but I'll just finish it here by saying- play it. Do not read too much into the review, do not look up playthroughs, just download, read the readme and fucking obey it. You might not have as good of a time as I and others, but you'll definitely come out with a better knowledge of Nolcoz and his style. 

4. Mana Vemputin by Smilecythe (jjj_smilecythe)
There's something of a theme between all of these levels I'm finding as I write this, I always think of myself as a gameplay-first kind of person, but good presentation can go a long, long way. So it's a good thing that Smilecythe has managed to be one of the most creative people in the community for both aspects despite having only released two levels as of yet.
His maps always feel so very influenced. If only there were more people who didn't give a fuck about the conventions, who couldn't give a toss about portions of the community whining that a level isn't for them, or that they cannot beat it, someone who is so singularly concerned with their vision of what Quake could be that they'll create both the most frustrating and interesting experiences just to have something up there.
Meshing intense visuals, a genius progression style, devilish platforming, fuckin' puzzles, and many different styles of combat and visual design, there's no doubt this is one of the best levels this year.
I fucking love Mana Vemputin, I fucking hate Mana Vemputin, Mana Vemputin is both the most frustrating and most interesting thing in Quake right now. Play. It.

5. Duel, in Towers by Muk (ad_muksp3)
The king of wizbrick1_5, the patron saint of stupid puns, the father of good smol levels. He goes by many names, but Duel in Towers is his best this year. It might not have a lot of textures (6 to be exact!) but it packs a hell of a punch, every area of the map is lovingly detailed in that signature wizbrick1_5 + wood trim, bringing the map together in a neat cohesion you don't see often with maps trying to constantly shoot for the moon in terms of aesthetic voice. The gameplay is fun, the visuals are neat, and it's got a healthy dollop of exploration to boot. A+, just some solid, solid Quake.

???. Gay Kisses for Christmas by Quasiotter (xj2020_quasiotter)
Okay, okay, maybe there's room for one more.
Quasiotter, ohhhhhh Quasiotter. Where do we even start? The community's sweetheart, the community's lovable scamp, the community's gay uncle. Quasiotter has made a name for themselves by now, in a way many other creators of his style haven't been able to- every time you open a Quasiotter map you're in for something different, something interesting.. Whether it's a level centered around using literal cheats to obtain novel facts about Dolphins, a light-hearted Quake quiz show, or a map centered around obtaining gay kisses from a cast of lovable Quake lads, nothing comes close to this level of novelty in Quake.
His levels are easy to write off if you're not into them, don't overstay their welcome if you are into them, and always have something interesting about them, even if that might not be your cup of tea (the map created out of textures made from his body parts was... the most creepy and horror-like thing in a jam based around such).
So that brings me to Gay Kisses for Christmas, an adorable romp through a trademark Quasi prototype world, every monster having their own little scenario, something cute to say when they're smooched, a little predicament you have to solve, it made my dumb gay heart flutter a bit each time I made progress, and that's gotta count for something.
It's weird, but it feels more like Christmas than all of the snow-covered, santa-filled maps in the jam. It's all about love, which is the real Christmas spirit if you ask me. (Did I just get to end a func message with a moral? that's a change). 

The one map I keep thinking about over and over again is Oxy Black Fortress It's an epic and stunning work and the gameplay is quite good.

I am biased on this one a bit but I loved JPal's Brick Red Old school feeling with great progression.

Jpal's follow-up Edge of Sanity was a completely different beast and had a fresh aesthetic and great nail biting moments.

No need to talk much about "Tears of a False God". It's a new benchmark and shows how beautiful a map can be in Quake.

So let's give Mazu some love: His sm207 map Ceremony in All Three Angles is the stuff of legend. I swore, threw my mouse around and had a stiff drink afterward. Had to god mode for a bit but it was still magnificent.

Back to Bal: Greenwood's re-working of his Kelluva Linna was a real treat. I hope to grab a scrap and make something new/old soon.

I haven't played enough Quake this year but I did watch a ton of streams, these are the 6 I played that really stood out.

There 

Good thread.

Bal's Tears of course, yah. Other folks have sung its praises well enough!

I haven't made it to the end of EoE yet, seems like I need to get cracking! Haven't played the Xmas jam yet either.

Hmm...

I've had a blast with JPal's output, especially the nostalgia-tinged first three releases. Just pipe that good old Quake right into my veins.

One release that I think a lot of folks slept on is Secrets of the Keep by MortalMaxx. Superb adventure through a town and castle.

Primordial by JCR (in CTSJ) floors me with how readable and playable it is while being *relentlessly* averse to using nice uncrumbled orthogonal walls. A+ atmosphere (and bonus for how the "outside" secret is handled).

Markie Music's Within the Flayed Kingdom (in Dwell) delivers beautiful colors/patterns, cool setpieces, and it's a joy to open up the paths and spaces. And apparently I have Terrorcotta to look forward to!

----------

I feel like I can't get out of this post without also mentioning Fairweather and Comrade Beep, although I'm waffling on whether to pick some individual map of theirs as being among the year's best. They've clicked into the "I'll probably like anything they release" tier for me this year (along with JCR and MortalMaxx). Beep's maximalist AD maps are rollercoaster rides, and I can just soak in fw's foggy warmly-lit towers/ruins aesthetic indefinitely. 

A little retrospective.

I haven't played Quake in probably a decade or so. I own the original game since the late 90s, but the disk is buried at the end of a desk drawer somewhere (hell I don't know even if the disk drive on my PC works anymore), so out of boredom during quarantine earlier this year I decided to buy the Quake pack on Steam, something I've been planning to do for a long time. To put things in perspective, outside a couple of test maps I've made decades ago, I had NEVER played other maps beyond the vanilla id ones. Not even the mission packs, which I've only got to play a few months ago.

Only after playing and replaying it all, I found on an old HDD a half-finished map I started 20 years ago and I decided to finally finish it. So I had to get up to date with Quake mapping (last thing I had used was Worldcraft), but that was when I accidentally stumbled upon two letters on my searches: AD. Like a man waking up from a decades-long coma, I was absolutely amazed by that. HOW all of that was possible on the good old Quake engine, to make maps look SO GOOD and detailed, while keeping the original aesthetic, even retaining the blocky, pixelated texture filtering? And expanding gameplay to new levels and scale as well, while still standing in familiar Quake-ish territory? Then, I found out there was a whole insanely active community, full of maps as detailed and mappers as skilled as those.

So, no, I won't post my top maps this year, since I've not even nearly played enough of them so I certainly won't do something justice.
All I want to say is thanks for you all. For creating such awesome maps, jams, packs, new texture sets, enemies, weapons, mods, everything. You were responsible for waking up an old passion that was dormant in me.

I certainly will release more maps in 2021! 

Trying to whittle down 2020's offerings to just five maps is a bit nuts, considering the amount of great content produced; however, here are some that really resonated with me & I would play them again:

1. Bal's "Tears of a False God"
2. Jpal's "Brick Red"
3. Mazu's "Ceremony in All Three Angles" (in sm207)
4. Nolcoz's "Obliteration Domain" (in EoE)
5. Zigi's "A Verdant Dawn"

In addition, I highly recommend playing both episodes, "Dwell" and "Epochs of Enmity," in their entirety. :) 

Thanks for the tips about Mazu's "Ceremony in All Three Angles". I had somehow managed to miss it. In the process of rectifying that and I love it so far. 

I still haven't played everything released this year. Deciding to try to only stream new releases is not so smart when you end up not finding the energy to stream...
But from what I have played, these are the most memorable 2020 maps for me :

- Engineering Mania by Mazu
I love Mazu maps, this is the one that turned me into a fanboy. Open layout, lots of exploration, you can feel lost but it's always easy to find where to go (the best feeling). It's got a good theme with a some nice twists and a super-cute super-secret. This map was a big inspiration for ad_tears.

- Mana Vemputin by Smilecythe
Like the previous map, also from the January Jump Jam (what a great jam that was).
This is my favourite map I hate the most, Smilecythe deserves to be locked up.
It's a real shame some more casual players will bounce off of this map cause of the difficulty. It's layout and smart puzzle recycling mechanics with the jump boots are something rarely seen in Quake, sometimes it feels more like you're playing a series of custom Portal challenges. The visuals as well are quite unique and very polished.

- Oxy Black Fortress by Heresy
Heresy nails the exploration with this one, the map has some faults I'd say, but the sense of place and discovery just works so well, with very distinct areas. Arcane Dimensions is a perfect fit for this style of map I feel.

- Vestigial by JCR
It's hard to pick one map from Dwell, the pack is so good overall and contains many gems. I don't think JCR's is the best map from the pack, but probably one of the most memorable cause of how crazy it is. I wouldn't know how to describe it really, if you haven't played it go give it a try (and play the rest of Dwell, each of the maps in that pack could've ended up on this list).

- Terrorcotta by Markie
It's hard to believe Markie has been with us for only a year, he gets my "Newcomer of the Year" award for sure. This is his best map so far, great visuals with smart and varied gameplay. Comparing all of Markie's releases this year would be a very interesting exercise in analysing rapid level-design skill progression, can't wait to see more from him! (and by that I obviously mean BurgerWorld).

It's tough to list only 5 maps, there are so many cool releases this year! I don't like writing stuff so much on forums, but I could chat for hours about releases and all the cool things that have been produced this year.
A final map I'd like to mention that I played recently without much expectations (I regret I didn't stream it now), The Mountains of Insanity by bmFbr (another newcomer), was a real treat!

Thanks again for everyone still producing stuff for Quake (not just maps, but also tools, mods, music, etc.) It definitely helped make 2020 a bit less shitty!

Oh and as a reminder, we have Quaddicted to track releases, but I also maintain a google-doc to track things a bit differently (otp started this in 2018 or 2017?) Mostly cause I like spreadsheets, lists, and numbers :
https://docs.google.com/spreadsheets/d/1pV4U_ttSB9hTq5YiBRXDUFwxL6b_FzMMzT3Gv26SX3E/edit#gid=691790069 

Some of these lists make me feel guilty for not including certain maps in my post

And Bal makes a good point about thanking everyone in the community. Music especially had a good year. We're lucky to have so many great people willing to make stuff for this game. 

Yah music, textures, tools, kind of an embarassment of riches lately. Could do a whole 'nother thread on that!

And I know some folks are reading this thread thinking "why didn't they mention X"... go ahead and post about X! You don't need to come up with 5 maps, or a detailed breakdown. Just get in here and post about a map that you loved in 2020. 

One thing I will note about Manu Vemputin for folks who will be giving it a try: the physics for the pushing-bars in the clocktower puzzle did not work for me using Quakespasm (normal framerate cap, on Linux, dunno if any of that matters). It worked when I tried it in FTE. Haven't tried QSS. That issue really soured me on it because it took me quite a while to find out that I was in fact trying to do the right solution. It really is a great map otherwise, and hopefully if anyone else runs into that problem they can get around it by using another engine. 

Every map you guys talk about here and:

The Lima Project
Deep Research
Retribution Revisited
The Veiled Bassin
The Mountains of Insanity
Primo
Abbeytoir
Curse of the Crystal Mines
Network Unreachable
Secrets of the Keep
Citadel of Twilight
... 

Some of those maps are from jams etc, so it would be nice if you said the package and author so it's easier to find them.

Glad to hear you liked my ctsj map, by the way. 

Other cool maps not mentioned above:

The Lima Project - by Comrade Beep
Deep Research - by Comrade Beep
Retribution Revisited - by Juz
Network Unreachable - by Juz
The Veiled Bassin - by h4724 (Coppertone Summer Jam)
The Mountains of Insanity - by bmFbr
Primo - by Remi
Abbeytoir - by Strideh (Halloween Jam)
Curse of the Crystal Mines - by Yoder (Disconcerting Unease 2)
Secrets of the Keep - by Maxx
Citadel of Twilight - by JPal (EOE) - I've enjoyed every map this person has done this year... at no time did I feel that he was a new Quake mapper!

Probably I've forgot a lot... I've played many of them in 2020! 

if you can only play one map from 2020, make it Witch House Mixtape:
https://www.quaddicted.com/reviews/ou.html

Also seconded on The Mountains of Insanity. Played that last night after playing sm211, and the teleport room in there is a treat. Good story to it as well.