Just wondering on what some useful stuff is, if there is any.

Also the fps_max command doesn't seem to work so how would I cap my FPS to 120?

According to my quick googling, the answer to your second question can be found here
www.neogaf.com/forum/showpost.php?p=13495119&postcount=60

And the first, http://left4dead.wikia.com/wiki/Console_commands

Hmm, thank you but I was more so looking for commands that would help for multiplayer, such as removing uneeded stuff like fog and what not, to help clear up visibility or something along those lines.

Also the download link on that FPS Limiter doesn't work :/

I just googled it, that's probably why.

The only way to cap your fps is to set refresh rate overide from your graphics card controls(may have different name in nvidia menu). Set it to 120hz, then turn vsync on in game.

I was thinking about that reddog but I remember trying to bump up the refresh rate that way and it only let's me put it to 75, but even when I do that, my graphics drivers like shit it self, so I have to keep it on 60 :'(