WowAce

Adds item values to chat messages.

Automatically leaves the global channels when inside an instance/raid and restores them when exited.

Uses guild notes to add alts' main names to chat windows and other places

vChat

Crowd-control monitor

Tooltip of socials button will now show which friends are online

TwiCo

Automate Your GDKP Auctions, Bids, & Payouts

Shows Chat as Combat Text

Captures chatframe Tradeskill Links for later reference in an easy to read format

Waitlist addon with EPGP Mass Award hooking.

Displays online guild mates.

Saves who searches in a favorites list.

Displays friend notes in unit tooltips, at logon, and in /who results.

ChatAssist2Options

Enables cooldown notification between players and allows party members access to each-others spell books.

BossWhisperer

Restores channels and channel-window associations after disconnects remove them.

Advanced Chat Filtering and Spam Blocking Addon

TalentWhisper