Echo GamePhones - 134,811 bytes.
Why hassle with RTS files when you can taunt your opponent over your mic? Software drivers included for Duke Nukem 3D and various incarnations of Doom that allow two-way speech during modem gameplay. Check this out!

Duke Nukem 3D Control Center for DOS/Win 95 - 2.56 Mb.
This is more than just a front end map launch utility, this program will allow you to alter just about anything in the game without corrupting the original game files. Why clutter your drive with a zillion utils when this one does it all (from a map launcher to CON file hacker)? Authored by Jeff Armstrong, a must have for even the casual Duke player!

Map Launch Utilities:
(for those that want just a map launch util).

edlev.zip - 32,275 bytes.
Utility written by jmooney@prolog.net which allows you to load up several DukeMatch user maps before the game begins, eliminating the need to break the current connection and redial your opponent every time you switch maps. Please read the documentation included with this utility, it is very important!

DukeMatch'er v1.12 - 14,598 bytes.
DukeMatch launch utility from Peter Reinhold. Please read the documentation included with this utility, it is very important!