WowAce

Provides access to all Portal and Teleport spells on right click of one button.

Lightweight but powerful auction house interface

Good old LibTourist-3.0 for WoW Classic Mists of Pandaria

Displays information about the current zone on the World Map, for WoW TBC Classic

A replacement tradeskill window

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

Aloft

Quest History tracker and shows lists of quests in each category

Achievements

Automated smart raid marking to speed up trash clearing in instance runs

Tracks the Blood Shield for Death Knights.

Calculates and shows your TankPoints in the PaperDall Frame.

Smooth combat HUD based on ArcHUD2

The core module for RW

Adds mob patrol paths to your map.

One large inventory.

Adds a status to Grid for debuffs applied by Raid Bosses.

Track time played, rested XP and money for all characters

Prat

Queing of /who and SendWho() queries and a much better interface (see docs), with gurantee to be executed & callback.