WowAce

Lists and/or reminds people missing flasks or food buffs at every ready check.

LFD status via a DataBroker display rather than the minimap.

Quickly builds /target macros for immediate use.

Adds 3 indicators to each side (top, bottom, left and right).

Tracks interrupts

A data broker plugin showing your longest fight and your current fight time.

Bang!_Libram_Swap

Drops the least valuable item in your bags to make space.

FuBar_SpeedFu

Enables cooldown notification between players and allows party members access to each-others spell books.

Prompts for canceling of pet battles if no rare pet is found in the opposing team.

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

RaidGroupNumber

Displays Currencies as a Data Broker source

A library that maintains a cache of items and their types.

Database of FlightMaster locations for HandyNotes

Shows you which bosses you've killed next to the raid finder frame.

Shows at-a-glance what raid buffs/debuffs you have.

Remaining and rested XP Data Broker plugin.

EyeCandy