> - Doom: WAD files were pkzip format
> - Duke3D: came with its own level editor
Add ioquake3 forks to it (there are many), such as Tremulous (massively modded, initially came from Quake 3), Urban Terror, Unvanquished (development is very active), etc.
(Tremulous mappers use NetRadiant.)
Anyways, you are absolutely right, although maybe I am just a boomer by now. I was 14 years old (along with many other players and modders) when I started modding Tremulous. I wish Tremulous was still active, but it is not. :( I still keep in touch with players from >15 years ago.
Pretty much all of Id Softwares FPS were pkzip wad files — or at least all of them up to Return To Castle Wolfenstine. After that point I had too many commitments to invest much time into modding so couldn’t say how they were built.
I seem to recall reading that their choice of wad architecture was intentionally to enable the modding community too.
"DPK format extends the legacy PK3 format with dependency mechanism and versioning", for example: https://wiki.unvanquished.net/wiki/Formats/DPK
BUT: "The archive format uses the PKZIP container (the well-known zip format) with a .dpk extension.".
Urban Terror. That's a game I haven't heard about in a long time. It must've been somewhere between 1998-2002 I played it. Damn, we even had a clan, and I played it on my Linux PC.
Does it still exist? If so, I probably get instantly killed if I dare to join any of the public servers...
Apparently it is still under development: https://www.urbanterror.info/news/blogs/ (last post is from 11 days ago).
There are players, too: "Online: 208 servers with 109 players" at this time.[1]
Fun times for sure! Bomb was my favorite game type. :)