WowAce

Creates virtual cyphered chat channels over guild addon communication channel.

Sphere

Resizes some default UI frames (GuildUI, LootFrame, RaidInfo, TradeSkillUI and TrainerUI) to show more lines

Instant PROC notification

Cartographer_Routes

Customizing your buff display

Provides information of tradeskill and crafting materials that are in the banks and bags of your characters.

Visual loot monitor

Good looking, smoothy and helpful nameplates

AltClick an item in your bag to add it a mail, auction, or trade frame, and alt-click to buy a stack if reagents.

Cancellation

Displays online friends.

Powerleveling guide framework

DeclineDuel

FuBar_WindFuryFu

Square Minimap and more

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Library to help with querying unit talents.

For Developers (of Addons which uses LibWho-2.0): show queues and queries in realtime

A library for PvP and Battlegrounds