[xdkyx]

There was a fantastic resource about Multiplayer Level design from David "DavidM" Munnich. Although done in Unreal Tournament context it was really informative. I don't know if it's still available (could not find it), taking into consideration it was hosted at the defunct planetunreal I doubt it survived.

[hnlauncher]

I think I found them on the wayback machine here: https://web.archive.org/web/20040603010041/www.planetunreal....

Are they the ones you're talking about?

[keyringlight]

Another one is Sjoerd "Hourences" De Jong, a lot of UE3/4 era stuff, which was around the era Epic made their engine widely available

http://www.hourences.com (no https on the site)

[Cthulhu_]

That's the one I was thinking of too, but also, how relevant is that still today? "Levels" in various categories of video games have evolved far beyond the fairly basic arenas of the UT / Quake era.

[amlib]

In terms of geometry density (detail) they have definitely improved by many orders of magnitude but in terms of layout I think most games have actually gone backwards with vastly simple levels to navigate. That (exagerated) meme about level design in 2010 is still fairly relevant [1].

[1] https://imgur.com/a/LfZouTK