WowAce

Keeps an eye on someone's distance from you, and alerts you if they get too far.

oUF layout looking like ag_Unitframes and Grid.

SCT_Cooldowns

A customizable buff/debuff display replacement for the default Blizzard frames (with right click cancelaura support).

A Latency Data Broker plugin.

Really very early stage. No, earlier than that.

FuBar_WaypointsFu

Draws 3D portraits for main units that can be moved or resized at will.

A library which provide tools for detecting adverse effects on units.

Shows all the targets in the raid

Converts commonly used acronyms into hyperlinks.

Tank statistics Data Broker plugin.

Add in keybindings to place raid marks on mouseover, or the target if there is no unit being moused over

GDKP gold run ledger

MouseLook

Display who did the Worship interrupting on Chogall

Allows raid leaders to view information on raid or guild member equipment information

LD50_armor

See all incoming casts on your target. Also includes resurrection monitor. Uses libhealcomm-3.0 and librescomm-1.0

Automatically converts a party to a raid when you attempt to zone into a raid zone without a raid.