General Commands
/help
Gives very general basic help.

/assist [name]
Assist your currently selected target, or target player if specified.

/cast spell
Cast the named spell, which may include the rank in parenthesis. For example: "/cast Slow Fall", "/cast Polymorph(Rank 2)".

/afk [message]
Toggle yourself as "away from keyboard". Typing /afk again will turn off AFK mode.

/combatlog
Toggle logging of your Combat Log into (wow folder)\Logs\PlayerCombatLog.txt.

/dnd [message]
Toggle yourself as "do not disturb". Typing /dnd again will turn off DND mode.

/duel [name]
Request a duel with your target, or target player if specified.

/yield
(/forfeit) Surrender to your opponent in a duel.

/emote message
(/em, /me) Emote the message.

/exit
Exits the game.

/follow
(/f) Automatically move to follow your current target.

/ignore name
Toggle ignoring target player.

/inspect
(/ins) Inspect the target player to see his equipment.

/logout
(/camp) Sit down and logout.

/macro
Open the Macro Interface

/macrohelp
Gives basic help on making macros.

/played
Show how much time your character has been online.

/pvp
Enable PvP for the next 5 minutes.

/raid message
(/r) Send the message to your raid chat.

/random number [number2]
(/rnd, /rand) Roll a random number between 1 and number, or between number and number2 if specified.

/remfriend name
(/removefriend) Remove a friend from your friends list.

/split money
Split the specified amount of money among your party members.

/target name
(/tar) Change the currently selected target to the specified player.

/time
Show the current game and server time.

/trade
(/tr) Initiate a trade with your selected target.

/who [string[ string2...]] [num[-num2]] [r-"race"] [c-"class"] [z-"zone"] [g-"guild"]
With no arguments, lists online players around your level in the current zone. string will list all players whose name, guild, class, race or zone contain the specified string. num[-num2] will list players within the specified level range.

/bug
Submit a bug report.

/suggest
Submit a suggestion.

/note message
Submit a message.

/script LUA-command
For UI creators.

/console command
For performing some game console commands, such as "gxrestart", "reloadui" and "quit".

/console settingname [newsetting]
For tweaking of game settings.

Group Leader Commands
/invite [name]
(/inv) Invite target player to your group.

/uninvite [name]
(/un) Remove target player from your group.

/ffa
Set "free for all" loot policy.

/master [name]
Set target player to be the master looter in "master loot" loot policy.

/roundrobin
Set "round robin" loot policy.

Chat Commands
/guild message
(/g) Send the message to your guild chat channel.

/party message
(/p) Send the message to your party chat.

/reply message
(/r, R) Send the message to the last player to whisper to you.

/say message
(/s) Send the message to people around you.

/yell message
(/shout) Send the message to people around you (very big radius, near zone-wide).

/whisper name message
(/w, /tell) Whisper the message to target player.

Chat Channel Commands
/chat
(/chathelp) Display a list of chat commands.

/join channel [password]
(/chan, /channel) Join (or create) the specified chat channel.

/leave channel|#
(/chatleave, /chatexit) Leave the specified chat channel, you can also specify the channel number.

/# message
(/c, /csay) Send the message to channel number #.

/announcements channel|#
(/ann) Toggle join/leave announcements on specified channel.

/ban channel|# name
Ban target player from specified channel.

/unban channel|# name
Unban target player from specified channel.

/chatlist
(/chatwho, /chatinfo) Lists all the channels you are on with their associated channel number.

/chatinvite channel|# name
(/cinvite) Invite target player to specified channel.

/ckick channel|# name
Kicks target player out of specified channel.

/moderator channel|# name
(/mod) Set target player to moderator status on specified channel.

/unmoderator channel|# name
(/unmod) Remove moderator status from target player on specified channel.

/moderate channel|#
Toggle moderation mode on specified channel.

/mute channel|# name
(/squelch, /unvoice) Disallow target player to speak on specified channel.

/unmute channel|# name
(/unsquelch, /voice) Allow target player to speak on specified channel.

/password channel|# [password]
(/pass) Set, change or remove the channel password.

/owner channel|# [name]
Display or change the owner of specified channel.

Guild Commands
/ginfo
Gives basic information about your guild.

/g message
(/guild) Sends a chat message to all members of your guild

/o message
Sends a chat message to all officers of your guild

/ginvite name
(/guildinvite) Invites target player to join your guild

/gremove name
(/guildremove) Removes target player from your guild

/gpromote name
(/guildpromote) Promotes target player one rank within your guild

/gdemote name
(/guilddemote) Demotes target player one rank within your guild

/gmotd message
(/guildmotd) Sets the guild's message of the day

/gquit
(/guildquit) Removes you from your guild

/groster
(/guildroster) Gives an entire guild roster (officers and leaders only)

/gleader name
(/guildleader) Sets target player as the guild leader (guild leader only)

/gdisband
(/guilddisband) Disbands your guild (guild leader only)