WowAce

Allows for gold tracking across multiple time frames

Allows you to loot BoP items without prompting when not in a group or raid

Durability Data Broker plugin.

Makes tracking reputation much simpler. By InSo(v)nIaX

Aggro Warning System for Parties and Raids.

Records mail when visiting the mailbox to make keeping track of mail and expiration dates easy.

OneChoice tries to help you reduce quest reward choices down to, ideally, one choice.

ArenaHistory

Never forget which one in that 5-mob pull casts what spell again.

LDB display for Oak Interrupts Broker

Scaffold

A Healing Assignment management addon

Fade Blizzard Raid Frames

Insanity resource tracker for shadow priests.

Social tracking suite.

Zone text Data Broker plugin.

Historian

Mutes Annoying Sounds

LD50_ap

Reports in the Default Chat Frame how many people does not have Well Fed effect, and who are they