WowAce

Allows you to create icons, which can be customized greatly by user's input. CiR is more than just the usual cooldown tracker.

Detox

Mapster's Minimap brother

Cartographer_Mining

InfiniBar-2.0

Broker plugin to display player orientation

Bidder

Omnibus

Library to help with querying unit talents.

Adds a couple of graph displays to Skada.

Displays the time remaining before your (temporary) pet is dismissed.

Piece of mind by being one with your class.

TuiRaidTracker

Doublerightclick casting, autolure and sound enhancing

MiniPet, Always keep your little companion with you, based on the work of Carra.

adds navigation buttons to Encounter Journal

Simple library that handles multiple levels of logging.

IncomingHealsLib

Shows activity for hidden ChatFrames by making their tabs flash.

Enhancer