Yeah we really should have a list of these, it's been like a year and no one has done this sooooo...
Important commands to know:
rp_toggleholster - bind a key to this, allows you to raise/lower your weapon
/dropweapon in chat - Self explanatory
Tab + right click - On players, allows you to give them money or tie them up if you have the rope item. On items on the ground allows you to pick them up in your inventory or use. Using a gun (either from your inventory or from the ground) puts it in your Scroll bar, you then select it like you would a gun in HL2 or CS:S
/sit - Puts you in the sit animation. /sit again to stand up
cs_leanleft - In console, makes your character lean against a wall. Type again to de-lean.
/me- Used for narrating actions, any RP server you've ever played on has this (needs to be in code because this forum allows for /me emotes)
/it - Same as /me but without a subject so you can describe te environment
/pm playername - Allows you to send a private message to a player with a PDA (all new players should have one of those in their inventory)
/ooc - Sends a global out of character message (Most RP servers have this)
.// - Sens a local ooc visible to people near you
/w - Whisper
/y - Yell
rp_listvoices (in console)- Lists any available voices you can emit from your character.(The sounds you are allowed to use depends on the flag.)
rp_voice (Name) - Plays the selected sound/voice. (Use rp_listvoices to find what you can use) (in console again)
/sitchair - Puts you in a sitting animation that you would usually use for chairs.