ElvUI - Itemlevel Tag

Custom buff and debuff overlays for Blizzard player, party and raid frames, with filters, timers, colors, tooltips and live preview.

Bringing back The Players ability to make "Meaningful choices" to track their teammates CDs.

Gilden Member Dashboard, Gildmaster Addon for handling all Gild Activity, Raid, Loot und Gearcheck

Better Cast Bars is a lightweight cast bar overhaul that improves visibility and control over enemy and player casts. It provides clear, customizable cast bars for nameplates, player, target, focus, and enemies.

X-Perl Forever brings the classic X-Perl unit-frame experience to WoW Forever, with compatibility fixes for its modern interface and protected-value systems.

Raid Bar is a useful tool that gives you faster access to marking and dropping world markers. A more appealing utility tool compared to the default blizzard UI.

Midnight Party/Raid frames.

Hide Anything is a simple and lightweight Addon, you can basically hide anything in your UI and customize many features which Blizzard do not allow to be hidden.

ViksUI Interface

Provides standalone so-called spotlight frames for Augmentation Evokers for Prescience management.

Alt manager and weekly tracker: Great Vault, Delves, raid lockouts, item level, gold, gear and talents of every character, in one account-wide view.

Debuff tracking, dispel and CC highlights, sound alerts, and quick-click actions — all in Decursive-style party frames. Pre-configured for all class dispels and talents, so it works out of the box. (Formerly SmartDebuff Reloaded)