WowAce

Assistance to the dance during Dread Spray

Lists and/or reminds people missing flasks or food buffs at every ready check.

A library to help with localization of Archaeology artifacts

Shows guild and system message of the day only if either one of them has changed since the last login.

On login, displays changes to your guild since the last time you logged in.

Bars showing amount of buffstacks

Adds indicators to the sides of Grid frames.

Improvements to the standard Blizzard Eclipse bar for balance druids. Use /ebp for the config screen.

GemList

Dynamically atering layout in raid environment (Tanks, Ranged / Melee DPS, Healers)

FuBarPlugin-2.0

Notifies you of experience gains

Checklist and notes addon.

Replacement for WoW's flash/fade functions.

Hitman

Adds resurrection, resurrected and soulstone status to Grid2. Uses LibResComm-1.0

agUF style oUF layout

BossWhisperer

Shows a money overview for your current realm in the tooltip on the money in your bags

GCInfo