WowAce

Proximo

Set and manage character notes that are displayed in unit tooltips and /who results.

Mutes various chat related annoyances while in capital cities and instances.

FuBar_WindFuryFu

LDB display of currencies, gold totals and session / daily / weekly statistics for all characters on a server.

Where the lore is at

UnitActionBars

Good old LibTourist-3.0 for WoW Classic Mists of Pandaria

AceBuffGroups

Shows where the equipment of inspected users or yourself is from.

Shows ZoneInfo on the World Map in a perfectly cromulent fashion.

Find five Ephemeral Crystals, get a pink hippogryph

Compact & customizable filtering, monitoring and grouping of buffs and debuffs

Simple Spell Alert

SRA

Raid loot tracking and text generation

Heads Up Display with Player and Target Info

provides enchanters with a decent tool for managing their profession

Display Garrison missons for all Characters

A lightweight addon that does something.