WowAce

Track friends / enemies in a convienent window, with optional logging

Managing and viewing loot-type rolls

ClassButtons

LibFriends-1.0

Adds PvP status to Grid frames.

allows you to flip cards of omens by spinning your mouse wheel; counts cards opened and money earned per session and lifetime

A small datatext for ElvUI-using Shamans that gives them accurate info about their Reincarnation cooldown

Shows the source of an item as a tooltip

Hide frames of people you've ignored.

Reputation

Dynamically creates your frames using a table structure and then operations can be done on your list frames

TradeskillInfoUI

Uses Loot-a-Rang on double right click

Notepad for Lua scripts and mini-addons.

World of Warcraft Textmate Bundle

KeepItCool

Adds simple coordinates to minimap frame

DragLib

An enhancement to the built-in raid frames to change color for debuffs.

Ancestral Fortitude / Inspiration tracker for Grid