Quake/Cheats

Protected cheats
The cheat codes that give you an advantage are locked down by the server in coop or deathmatch. You can't activate or modify them.

Unprotected chates
Some cheats can be used at any time, even on remote servers. While some servers are modded to lock down these cheats, most do not.

These cheats can be obtained simply by scanning the Quake source code, and with the availability of the source code, aren't exclusive.

Some of these cheats require being either the sole player, or the server.