[RussEfarmer]

Here's a table of literally every console command in vanilla Garry's Mod as of June 2015.

Some of these commands aren't documented very well because of their lack of use and lack of help text. Google will usually help you find exactly what a command does if it's at all useful. Additionally, the Valve Developer Wiki will sometimes have good information on some commands, but not ones exclusive to Garry's Mod.

The in game command to find this list is cvarlist [search text]. cvarlist voice will show you any command related to voice, and cvarlist sv will show you all commands that have "sv" in them.