WeakAuras is a powerful and flexible framework that allows the display of highly customizable graphics on World of Warcraft's user interface to indicate buffs, debuffs, and other relevant information. This addon was created to be a lightweight replacement for Power Auras but has since introduced more functionalities while remaining efficient and easy to use. And now WeakAuras is available for World of Warcraft Classic!
Features
An intuitive and powerful configuration interface
Custom textures including all textures from Power Auras and Blizzard's spell alerts
Progress bars and textures that show the exact duration of auras
Displays based on auras, health, power (mana, rage, soul shards, holy power, etc.), cooldowns, combat events, runes, totems, items, and many other triggers
Preset and user-defined animations
Custom side-effects such as chat announcements or sounds
Grouping, which allows multiple displays to be positioned and configured at the same time
CPU optimizations such as conditional loading/unloading of displays, modularity, and prevention of full aura scanning
Powerful customization options, such as animation paths, on-show/on-hide code, and custom triggers, for Lua-savvy users