No one seemed to mention this (or the prior link is down), so here is a working link for Quake I pre-alpha test. As far as I know, its exclusively a multiplayer build.
Download: http://www.quaketerminus.com/tools/qtest1.zip
More importantly does anyone know anything about a Hexen 2 pre-alpha build. It has been definitely leaked to the public in the late 1990s and was floating about on the internet, but I have never seen it. Can someone help, or is it lost forever????