WowAce

Provides info about spell teaching items.

Reslack

A library to convert ItemId to ItemId of player's faction

Adds tooltip for debuffs (and other things? you found out: no).

Tools to easily compare gear among party members.

Uses linear regression and a log of hitpoint values to estimate how long a boss has left to die and reach execute range.

Very very simple tooltip

StreamBuddy is a World of Warcraft AddOn that will make your life, as a streamer ingame, easier!

CatFight

HuntersMark

Show who is targeted by at least one enemy, and the casting progress of the incoming spell.

RepWatch

Broker_Durability

oUF_HolySmurf

SimpleBar

A library for manipulating UTF-8 strings

Advanced features for sRaidFrames

AHsearchNext

FuBar_CustomMenuFu

Gnomish math at its best!