Slash Commands:

Chat:
/chan joins your realm's (Order or Destruction) general chat channel
/chancreate creates custom channel
/ sends a message to the designated channel
/s sends a message to the say channel
/t sends a private message to the named player (Note: Pressing the "R" key will let you reply to the last tell received)
/p sends a message to your group members
/g sends a message to guild chat
/wb -chats in Warband
/aos - chats in the alliance officer chat
/as (/a) - chats in the alliance's main chat
/reloadui - relaods your user interface


Emotes:
/wave
/bow
/beg
/point
/talk
/charge
/salute
/shrug
/no
/yes
/scream
/sit
/kneel
/lie
/eat
/drink
/yawn
/burp
/cower
/mad
/bored
/cheer
/clap
/flex
/laugh
/cry
/shy
/dance
/time
/drunk
/bye
/hi
/cheers
/chicken
/pig
/rude
/yell
/stomp
/brandish
/beckon
/halt
/howl
/gloat
/belch
/katadance
/rogor
/rez
/slit
/smile
/frown
/happy
/lol
/taunt
/shout
/glare
/intimidate
/waaagh
/grumble
/weep
/think
/insult
/preen
/primp
/scratch
/pick teeth
/impatient
/smoke
/no beard
/showoff
/dropkick
/chase tail
/sing
/plot
/conspire
/dagger
/pray
/juggle
/disagree
/agree
/em allows a custom message to be sent to the emote channel (your character name will be the first word in the emote followed by your message)

Note: This is not a complete list. Emotes can be used with or without another player targeted, and the message will change accordingly.


Ranks:
Alliance Leader: kick/invite/promote/demote/aos/as
Alliance Officer: invite/promote/demote/aos/as
Alliance Member: read/write in as
Alliance Initiate: read as, but no typing (shuts up the new players -- or the ones with colorful post-RVR death language (like me))

General:
/friend adds the named player to your friends list
/assist allows you to target another player's target
/follow allows you to follow the targeted player
/bug submits an ingame bug report
/respec resets every trained ability, tactic, and morale as if you were level one and had never talked to a trainer before
/refund XXXXXX (Actions|morale|Tactics|Spec)
/stuck transports a stuck charcter to the nearest respawn location
/help brings up a list of all slash commands (not true)(but getting better)
/aid it's /assist for getting defensive target
the - on the Numpad for taking screenshots.
/gc apromote - Promotes the player's alliance rank
/gc ademote - Demotes the player's alliance rank
/gc invite invites named individual /targeted individual