Whether you want to track your damage, master the Auction House, or simply track your progression you will need addons.  Here is a short list of known working addons with Wrathgate.

Altoholic - Track all your characters in one place regardless of which character you find yourself playing on.

Auctioneer - Become the master of the Auction House with this do all addon.

Bagnon - Combine all your bags into one panel.

Bartender - Create the hotbars you want.

LeatrixPlus - Automate some basic features of the game like selling greys, repairs, or even group invites.

Minimap Button - Puts most of those buttons all in one neat place without overloading your minimap with buttons.

MultiBot - This addons helps control the bots you add to your group or raid.

Overachiever - Don't miss out on a single achievement task with this addon.

Postal - Gives you the power of automating some basic mailbox commands.

Prat - Customize your chatbox to suit your needs.

Questie - Helps find those hidden mobs and lets your group know your quest status.

Warmane AH Fix - This addon is required if you are going to be using Auctioneer.