I was doing some research today, and I came across what appears to be a little-known title with Glide support.  Sierra/Dynamix had a project to produce a flight simulation called Desert Fighters which was cancelled in 1999.   Before its demise however, the project did issue an "alpha tech release" multiplayer demo.   The documentation indicates that this ATR supports not only OpenGL, but Glide (Voodoo2 specifically) as well.  Here is a link where you can get the ATR:

http://www.3dgamers.com/games/desertfighter/downloads/

Here is a report created prior to cancellation of the project:

http://www.combatsim.com/htm/aug99/desert1.htm

Well, an enterprising individual might be able to modify the Red Baron 3D server (freely available as rb3d_svr.exe) and/or the Desert Fighters ATR to create a usable multiplayer environment.  I doubt that Dynamix would have created a server/multiplayer environment from scratch if they had the Red Baron 3D code available, and the server executable itself is quite small (300 kb).  The environment (supplementary files) might pose a problem, but I would expect them to work on the pattern of the Red Baron 3D files.

I tried installing the ATR for use with a Voodoo5, and although it runs (i.e. the menus work), it has what might described as a "palette issue" (colors are all wrong).