WowAce

EBB adds groups of bars to your screen showing you which (de)buffs currently affect your toon or some other units.

Enables multi-line/unlimited-length pasting of text or commands into WoW

Antagonist

MorgDKP

Tracks vulnerability debuffs on multiple mobs

mount and companion manager

Adirelle's unit frames, based on haste's oUF.

A simple combat log that displays events similar to SCT

Show buffs on nameplates.

Incubator

tracks and share quests between your party

Tracks the HoTs you cast.

Watches your chat, flagging missplled words, and offering correctly spelled suggestions.

Marks the locations of Hallow's End candy buckets on the worldmap and minimap.

Display aura information inside action buttons

Library that tracks incoming heals

Alternate Power- and Combopoint/SoulShard/HolyPower-bar

Questing minion

Raid Frames using the oUF framework.

OneBag is a replacement for the default game bags that combines all the bags into one frame.