WowAce

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

Small addon to copy chat lines.

AllYouCanEat shows information about the following statistics: beverages, foods, bandage types, potions, elixirs and flasks.

Capsule

A simple addon that warns you if your pet isn't attacking while you're in combat.

MAcon

Action button layout and configuration

Pop a chatframe warning about guild battle standard when boss health reaches 30%

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

Displays Currencies as a Data Broker source

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

MagicMarker_Data

ezIcons

Adds an additional spell alert if you have more than one charge of a buff that is normally tracked by the in game spell alert...

Notifies you when you get aggro.

ChatAssist2Options

Adds Buff/Debuff icons to the grid frame.

This is an add-on to block incoming guild/party/duel requests (except for friends/party/guild) (previously ASSBlock)

EBB-inspired buff bars with click-to-remove support

Aggro notification library.