WowAce

Add-on that shows in a unit tooltip window a number of killed mobs of the same kind

How many quests do you have in your log? ;)

Simple and super light-weight tracking of profession links for all your alts.

Displays friend notes in unit tooltips, at logon, and in /who results.

Healer gear benchmark

Shows mana usage as a percentage in a spells tooltip.

Shows the spec of people around you in the tooltip.

Makes your item stats shine!

Tooltip of awesomeness. Moo. It'll graze your pasture.

StarTip (Tooltips from Outerspace)

Provides shareable notes and other information for your guild, party and raid community.

Should I send that recipe to my alt?

This will keep track of how much you have paid per item in your inventory. Only one of (Auctionator, Auctioneer, AuctionLite,...

Dynamic item DKP calculation

Shows loot information in item tooltips

Tooltip of socials button will now show which friends are online

LibDataBroker plugin showing some random XP related data

Shows the source of an item as a tooltip

Creates a broker plugin for all your broker launchers

A system config addon to WOW