WowAce

TableTopLib

Bidder for DKP points. Usable as standalone bidder, or with DKP - Manager to manage points.

Adds notes to item tooltips

TrapBar

A library to return spell duration and debuff type of a spellID.

WF3sec

DHUD2

GearRating

HazLoot

Cartographer_Mailboxes

Makes your item stats shine!

Tracks whispers and conversations

Quest helping: fetching items to use, that sort of thing.

Keeps track of time played and rested XP across your characters.

A library to try to guess a level of a player.

Shared handling of media data (fonts, sounds, textures, ...) between addons.

Lets you drag UI frames around

Timerbar embeddable library

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

Tooltip scanning library.