Doomseeker is a cross-platform server browser for Doom. The goal of
Doomseeker is to provide a smooth, consistant experience for Doom players
regardless of port or platform. Doomseeker provides support for Zandronum,
Chocolate Doom, Odamex, and Vavoom.

The first time you run Doomseeker, you will have tell it the location
of your Doom engine binaries and IWAD files. It won't look in your
PATH for the binaries, they'll be in either /usr/bin, /usr/games,
or similar. If you don't know where your IWAD file(s) are located,
try /usr/share/games/doom.

This requires one or both of chocolate-doom or odamex (at least, to be
useful for anything, it needs at least one supported Doom engine).