WowAce

Adds tier set number and difficulty indicators to tier item tooltips.

Sneakily inspect how much gold your mouseover target has made so far.

Calculates the relative value of attributes towards physical dps.

LibQTipClick-1.0

Shows where the equipment of inspected users or yourself is from.

Ratings

Item link modification

"Your quest log is full". How many quests do you have in your log?

Enables RatingBuster to calculate selected buff effects even if you don't really have them

Very very simple tooltip

Tools to easily compare gear among party members.

Really very early stage. No, earlier than that.

Tooltip text modiffier based on DogTag.

Pre-Alpha of SpiderEyes power desplay. Do not distribute!!

Shows the Guild Achievements Points and Members in the tooltip

Shift-clicking on a user name in chat shows a tooltip with their whois information.

Shows what stat was reforged in item tooltips.

Adds information about the items tokens can purchase and vendor location to tooltip

Adds tooltip for debuffs (and other things? you found out: no).

Watch tooltip updates to announce when you find specific objects