WowAce

Displays an alert whenever you loot an item for the first time.

Scans your Equipment for cumulative item bonuses and sums them up.

DeuceCommander

Provides a quick display for the LFG Call to Arms

LilSparky's Workshop mod for Trade Skills

QuestAnnouncer

A volume control for Data Broker.

Quickly assign the highest follower to each building or unassign all of them.

aUF_RangeCheck

In-game EPGP guild helper, supports standby, main/alt shared pools, minEP, offpecGP. Fixed price list with progress multiplier.

Displays the time until the next battle and more.

InstanceMaps

Add-on that allows you to setup and quickly switch between different profiles of your action bars

Campaign maps for Warcraft Conquest Moon Guard server

A Data Broker display for combat statistics.

Raid Cooldowns

Battleground Timers in a HUD around the Blizzard BG status

Display the global cooldown around your cursor. (+ other stuff)

CharScanner scans Basic Character Data, Talent Specifications, Equipment, PvE/PvP Achievements, PvE Boss Kill Statistics and ...

Reno is a slash-command that can patch predefined options in a macro to change which abilities will be chosen.