WowAce

Shows the group leader, raid assistants, and master looter in Grid.

Shift-clicking on a user name in chat shows a tooltip with their whois information.

Smooth combat HUD based on ArcHUD2

Adds Blizzard, oRA2, oRA3, CT_RA MainTank or Dungeon Finder Tank icon (shield or MT, 1, 2 ... 10) or text (MT or MT1, MT2 ......

Good looking, smoothy and helpful nameplates

Keeps track of important de-/buffs in a splash screen

Notifies you of new calendar event invites and reminds of upcoming events on all characters and realms

One Click Forced Exit / Logout / Reload UI button for Broker

Light-weight enhanced casting bars

Adds unreal tournament style sounds to PvP encounters.

FuBar_IOPFu

User-configurable protection for your inventory. Automatically buys back mistakenly sold items.

MeleeFrame

Adds a Friendly Fire mode and data collection to Skada.

SpellEventsLib

Reports the total threat on a mob at the end of combat.

LibRockEvent-1.0

Crush Chance

Skip the gossip and select the normal NPC action

Really very early stage. No, earlier than that.