Hello again. I have uploaded screenshots to aid in finding the secrets. Note that I did not use the readme to hunt for them, so for the most part they are listed in the order I found them during multiple subsequent walks through the map.
I hope these are useful for those not able to find the secrets themselves or those who can't find them with the directions in the readme.

https://reubzaet.home.xs4all.nl/quake/Quake%20-%20The%20Forgotton%20Sepulcher%20-%20Secrets.zip

I'm still trying to find out what the message about the LICH means though...

Have fun! 

76mb for some pics? 

It's 284 jpg files in 1680x1050, so considering that it's not so big at all :) 

so glad someone such as yourself took the time to do this, as it was driving me nuts :) 

https://imgur.com/a/4TUlY 

https://twitter.com/ItEndsWithTens/status/909229463988252674

I don't have a Youtube video up yet, for obvious reasons, but I wanted to chime in now and thank Wouter for the screenshots! I got the first 44 secrets unaided (over the course of six and a half hours and only on normal, but I'm still happy with myself), and the next four with some resourceful poking around (restarting the map to check a thing or two, noclipping a few times to rule out dead ends), but the last two eluded me for a long time and I eventually had to admit defeat. Wouter's screenshots helped me find them; it turns out they were in areas I thought I'd already thoroughly searched, and if it weren't for those shots I'd never have thought to go back. I'm grateful for the effort put into the readme, but trying to attach the text descriptions to the secrets I'd already found was too far beyond my mental faculties. I'm dopey, I need pictures. :)

As far as map feedback, I'll have my first-play video up sometime in the coming week (I hope), but basically, a mind-blowing accomplishment! The architecture, the texturing, the sense of "thickness", layer after layer of construction one epoch after another, the sound design (holy shit the sound design), and of course the secrets. Cute shoutouts to community members, tons of fun rhymes, mechanisms left right and center. Goes to show how much map you can pack into an 8k cube. I'm still reeling.

On the critical side: the loop-de-loop roundabout flow, while providing a great "lost in an alien dimension" sensation for just playing start-to-finish (i.e. like a normal person), roughed me up a bit in the hunt for secrets. But I suppose that is my own fault; Sepulcher really drove home how much of my frustration in secret canvassing is my own psychology fighting against me.

I also feel like the end fight might have benefited from a Fire Shambler or Boglord? Something big, in other words. Felt like it could have been more of an event, given the scope of the adventure before it.

Finally, as much as I understand the need for promotion, having followed sock on Twitter for a bit now I did feel like the impact of some of the more striking secret areas was diminished by having seen preview screenshots. Still put a smile on my face to actually get into them, but I think I'd have been positively floored if I didn't immediately recognize the areas.

All in all something to be immensely proud of! Now if you'll excuse me I have almost nine hours of video to edit. 

thanks to yer diligence and hard work, i have now located the last three secrets.

S03 was the hardest.

S38 and S42 were kind of more 'obvious', and i was blushing that i didn't spot them! 

Serious dilligence in the map that deserves it. 

Thank you all for your feedback on the screenshots! I'm really glad they are useful. 

@Bloughsburgh
List of secrets are provided in the ad_sepulcher_readme file.
Missed that. Still, like Tens said, screenshots beat text description. Anyway, I'm glad at least some of the mappers are picking up after your example. I'd like secrets lists to become the norm in map readmes. 

I actually just enjoyed paging through the screenshots without actually using them for secret-hunting. Reminded me of the days of screenshot-heavy map reviews and "strategy guides" before YouTube. (But better lookin'.) 

I'd like secrets lists to become the norm in map readmes.

That's something I am NEVER going to do. If someone is that curious they can "noclip 1" around my level. But that's lame too. 

No 1 needed. And I very occasionally do that if I can't find something after spending 1/2 hour on one last secret. 

Ha! Now if we can just keep mappers from using targetted trigger_secrets and force Quakespasm to draw entities when outside the vis'ed area. 

Yeah okay, it's a toggle, but for me it's "noc" + TAB + ENTER

@Qmaster

Secrets are more fun when in a separate area IMO but I get you. In any case, Sepulcher is a really special case with these insane amount of secrets. 

the way the old adventure game hintbooks used to do it. each puzzle has a short list of suggestions provided which start vague and become more and more pointed before offering the giveaway as a last resort. you could cover the spoilers with paper and read only as far as you needed, and still have the revelation yourself and feel clever for it (just marginally less clever).

it might also help mappers notice if their secrets are too repetitive. 

If someone is that curious they can "noclip 1" around my level
Some secrets can't be found via noclip, and I don't know what some mappers do to their maps but they somehow make it impossible to see anything when noclipping outside of the geometry (NewHouse's maps especially come to mind).

Why would you NEVER put the secret list in the readme? 

Why would you NEVER put the secret list in the readme?

Because I feel like players should find them themselves! I found the Dopefish in Quake myself. That was a magical moment, especially because it had been hinted at in the start level. 

Isn't it a bit unfair to the less perceptive players? Notwithstanding the fact that sometimes, secrets aren't well enough hinted at... (Of course, a secrets guide must be used as a last resort, but it can be really helpful in those cases) 

I am one of those less perceptive players!!! haha. No I stand by my choice. It's funny too because my Speed Map 179 map secrets were pretty tough to find and Ch0w even did a dedicated video and spent a bunch of time trying to find them.

If they had been in the readme I assume he would not have been so happy to have found them.

Now some mapper's secrets are INSIDIOUS. I am talking about Ionous' Jam9 map. I found two of them but I gave up after about 30 minutes looking for the rest. 

I could find the kraken, but not the lich fiend. Did sock or giftmacher confirm its existence? Since some monsters appear to spawn, I don't think the monster counter is reliable. 

Check the readme. I think it details all the secrets and related stuff. I think in AD the monster counter is dynamic. If you trigger a monster and it spawns into the level than it's included in the monster count. 

Wow, thanks, I hadn't noticed that the secrets were listed there. Unfortunately it didn't solve the mystery. I'll keep searching for it. 

I haven't checked 1.70 code yet, but in the previous release, the lich fiend code was incomplete. Perhaps a planned boss that was scrapped, but still makes for a neat secret area macguffin. 

I did a somewhat long and derpy playthrough of this which you can watch here:

https://www.youtube.com/watch?v=wnRTYyQrkPA&list=PLzplQrZpMjlbiVqkKXID0JguzUTrv4V_J