Effect - Code
Change brightness - lightgamma
Change framerate - fpsmax [number]
Disable background sound - stopsound
Crosshair Change:
To make it so your crosshair won't get bigger when you move. type to go into console, hit spacebar once and type cldynamicxhair 0 .
Display ping values:
Start the game server with the -numericping command line parameter.
Turn Off Background Sounds:
To turn off background sounds so you can hear footsteps and real fire better type stopsound in the console.