WowAce

Disease Tracker for Death Knights.

RicoMiniMap

Shows your standings with the factions.

Keeps track of HoTs, DoTs, Buffs and Cooldowns. With audio and text alerts to refresh them.

Gathers statistics on certain chance-on-use spells, also known as procs.

MountUp

Improved Quest Tracker

YssGuildShop

Generates and posts random Chuck Norris facts to a specified chat medium.

Friends & Guild Data Broker plugin.

A library for PvP and Battlegrounds

Provide plenty of links

NBuffBars

Omnibus

Helps you automate selling stuff.

Adds on-screen buttons for the farming tools and seeds.

Tracking and ranking of dps/hps in a guild.

A collection of useful (guild management) tools and utilities for smarter than average bears.

Tracks profession specific cooldowns and items across all your characters

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