I believe many of them come from
http://www.md2.sitters-electronics.nl/models.html, although obviously the ogre with an axe in his back is not there.
I had a look through, and there's a real mixture of stuff in there. The modern stuff like the vehicles isn't all that useful for quake, and often didn't covert to the palette all that well. I would use the fire hose in a base map though, possibly after muting the red a bit! At the other end of things, the Egyptian stuff looks great and obviously there's a matching texture set.
The medieval stuff is somewhere in the middle - stuff like the torture equipment could appear naturally in a quake map. It could all do with some new textures though - not because the textures converted badly. Rather because the wood texture doesn't really match any quake texture sets. It would blend in much easier if it matched dull wizwood, for instance.
There's a few other places where I longed for different skins. The great big tech-crate is a lovely design but at the moment would look out of place in idbase, ikbase, spdbase. It'd be great to have a texture for one of them. The teleporter pad is a cool model but plain sliver gunmetal is basically never found in quake tech maps. Also little things like fullbrights would be nice - it's good that there are no unintended ones, but models like the branding iron could use proper ones (I'm working on a quick fix for this particular model).
On a technical nitpick, quite a lot of the skins are 480x480 in size - maybe the source models were the same. I'd recommend reducing them to 256x256. One reason is that skins are best off in powers-of-2 dimensions, at the moment your 480x480 skins are being stretched to 512x512 in glquake. The reason I'd take the textures down in resolution is because often these models have much higher pixel density than the surrounding map. Moving them closer will again help them blend in.
I know that's like 4 paragraphs of suggestions but I only bother with any criticism of things that I like and want to see being great. It's really cool to see new detail models for quake finally appearing, and I hope to see maps make use of these.