WowAce

Collects Herbs, Mines, Gas Clouds, Archaeology, Treasure and Fishing locations and adds them to the worldmap and minimap

A library that handles the basics of "window" style frames

A library to help with localization of in-game subzone names.

Adds spec switching support to individual AceDB-3.0 databases.

Replacement for the default UI's StaticPopup dialogs.

Compression and Decompression library

"Debug" code free since '93!

Displays additional information for Mythic Keystone dungeons

A Replacement for standard UIDropDownMenu

Give whispers an instant messenger feel.

Afflictions display and cleaning for solo, group and raid with advanced filtering and priority system.

Replacement for ActionButton_Show/HideOverlayGlow APIs

A library to help with localization of bosses.

Adds mob patrol paths to your map.

A library to help with localization of races.

Restores access to removed interface options in Legion

Tracks rare drops, including companions and mounts

Angry Assignments

Library that handles chat output.

Adirelle's bag addon.