This will be one of the harder lists to update. The reason for this is because, there's different commands on every server. I'm going to give a general command list, which means they're the same on many servers, mostly all of them.
Player Commands:
::char,::look - Change your characters appearance
::players - Check how many players are online
::afk - Your player will yell I'm AFK
::info,::help - Usually pulls up help for the server
::yell - Yells a message across the server where everyone can see
::commands - Pulls up commands list (Usually)
Moderator Commands:
::noclip - Allows you to walk through walls (Not all moderators can do this on some servers it will ban them)
::tele ####,#### - Enter numbers in the #'s, this will teleport you to the coordinates you entered.
::kick, ::kickuser - Kicks the player off the server, enter a name after the command
::mute - Will mute the player specified
::ban, ::banuser - Bans the user specified
Admin/Owner Commands:
::god - Enables your character to fly like super man (Not on all servers)
::xteleall - Teleports all players to where you stand
::pickup #### - Spawns an item depending on what code you enter in
::npc #### - Spawns an NPC depending on the number entered
::pnpc #### - Changes your appearance so that you're an NPC of some sort, depending on the number entered in
(Admins and owner also have the same commands as everyone else below them)