Extra Characters: If you want to have more to choose from at Multiplayer Practice and Non-Laddered Games, press F8, then enter extras fnkqrrm. If you have the unpatched version of the game, enter extras quantifigon instead. When you are at the Purchase Terminal, hold down alt when clicking on either Characters, or Vehicles.

Multiplayer Cheat List:
Press the tilde key (above TAB) during gameplay to activate the console. Then, enter these codes:

Enable extras cheat — extras fnkqrrm

Message to all clients (host only) — admin_message (message)
Message to all clients (host only) — message (message)
Toggle framerate — fps
Display game progress — game_info
End current game (host only) — gameover
Ban user from the game (WOL server only) — kick
Set max net update think rate (per second) — net_update_rate
View player info in console — player_info
End game and quit to O/S (dedicated server only) — quit
Shutdown slave server (dedicated master server only) — quit_slave slavename
Quit to desktop and restart process (dedicated server only) — restart
Toggle pixel bias in screen text — screen_uv_bias
Set total bandwidth budget — set_bw_budget_out (bps value)

Infinite Skirmish Time: Create a backup copy before proceeding because this involves editing a file of the game.
Open svrcfg_skirmish.ini (in the drivepath:\westwood\renegade\data directory) with a text editor.
Change the GAMETIME value to numeric zero (0) to remove the time limit. Also, you can change the initial credit.