Must Have
    WeakAuras example image.
    No brainer nowadays. Goes together with website.
    Probably the number 1 must have addons of all, as it goes from ability timers, boss fight utilities, cooldown trackers and many more. If you don’t know WeakAura, you’re missing out on something big.
    Boss Mod: BigWigs example image.
    Boss Mod: BigWigs
    Boss Mods are those addons which keep you informed about boss timing abilities and things going on in a raid fight.
    BigWigs is one of the two big existing Boss Mods. It's more quiet by default and offers great customization to set it up to your tastes for each fight. Arguably best IF you take advantage of the customization.
    Install either BigWigs OR DBM, but not both.
    Boss Mod: Deadly Boss Mods example image.
    Boss Mod: Deadly Boss Mods
    Boss Mods are those addons which keep you informed about boss timing abilities and things going on in a raid fight.
    DBM is similar to BigWigs and another very famous Boss Mod. It's arguably more beginner friendly. “Louder” than BigWigs by default, it’s more oriented toward helping you react.
    Install either BigWigs OR DBM, but not both.
    The addon is directly connected to Raidbots and only retrieve the text you will provide Raidbots to sim. Simming allows you to compare your gear/talents/conduits to find the best DPS upgrades/setup available. When you reach a certain level of progress, that’s the only relatively accurate tool that exists.
    Mythic Dungeon Tools example image.
    Mythic Dungeon Tools
    A reference for planning ahead your route or importing recommended ones. You can also use it to check trash or boss abilities.
    LittleWigs example image.
    Boss Mod timers for M+ boss fights. BigWigs and DBM are only supporting raid fights. Requires BigWigs to work.
    A ranking system for M+. It is as imperfect as mandatory nowadays, but still does a better job at building/joining M+ group than pure iLVL.
    Angry Keystones example image.
    Angry Keystones
    Improves the default UI for the key timer and progress. Also automatically puts your key in the receptacle to be ready to go.
    Screams at you when you’re standing in a zone you shouldn’t be in.
    Astral Keys
    Quality of life addon for things around M+. Displays the keys of other players in your guild who have the addons, automatically links your key when someone says "!keys" in a chat, improves Blizzard's UI of the weekly affixes, and other features.
    Plater Nameplates example image.
    Plater Nameplates
    The "WeakAuras" of Nameplates. Plater has a lot of customization and tooling available, and comes in with built in plugins that are fantastics. even has a section about it.
    KuiNameplates example image.
    A great alternative to Plater, with less customization and modules.
    Tidy Plates example image.
    Tidy Plates
    Another alternative, with bundled themes you can quickly setup.
    Threat Plates example image.
    Threat Plates
    Yet another alternative, quite minimalistic.
    OmniCC example image.
    Displays numeric texts on top of each action button, so you can better see when your cooldowns/abilities are ready.
Unit Frames
    Shadow Unit Frames example image.
    Shadow Unit Frames
    Display players or NPC's health, resources, buffs, etc. Replaces Blizzard default UI. SUF (Shadow Unit Frames) is the most popular and still updated option.
Raid Frames
    A good option for a simple Raid Frames replacing Blizzard's UI in an elegant way. For anyone who's not already deep into Vuhdo, probably the best pick. Healers, consider using it together with Clique for mouseover casts.
    A very powerful yet very complex Raid Frames, built for healers mostly. Offers a heavy amount of tools that in the past were unique, but have become part of the native WoW UI nowadays. Not sure Vuhdo would still be the go to for players not used to it in Shadowlands.
    Shadow Unit Frames
    SUF also offers the capability to do Raid or Group Frames, so if you're already using it for Unit Frames, you might as well use it for groups.
Action Bars
    Bartender example image.
    Replace Blizzard default's action bars, allows you easy keybinding of spells and more resizable, movable and customizable bars.
    OPie example image.
    Less famous and more recent than Bartender, OPie allows you to customize a wheel that you keybind to make it appear. If you're out of keybindings, it's a fantastic alternative to mouse-clicking.
Cast Bars
    Quartz example image.
    More advanced and customizable cast bars. Since interrupting and keeping track of casts in M+ is such a gigantic part of a dungeon key's success, it's everyone's responsibility to use the tools that will enable them to be fully alert.
    Prat example image.
    Replacement for Blizzard's default chat. Bring several quality of life, like clickable URLs, customizable design, coloring of player names, etc...
    Chatter example image.
    Similar to Prat, many quality of life improvements for your in-game chat.
    Filters bot spams in your chat, making public channels (for people who haven't already left them) less noisy.
General UI
    A fully featured re-layout and re-design of the original WoW's UII It comes with several pre-configured tools and features improving on the native solution. A lot of customization and options are available to make it to your taste too. You'll also be perfectly fine without ElvUI, no worries.
    More focused on the pure Chrome, SUI is also a re-design of the game's UI. It doesn't have such a heavy development team behind though, and has a smaller scope. Yet if you like how it looks, just roll with it.
    Clique example image.
    Allows you to easily bind action to mouseover, be it from your mouse or keyboard. Great utility for healers and tanks, or any class using support spells on friendly targets.
    Exorsus Raid Tools example image.
    Exorsus Raid Tools
    Must have for raiders. Allows you to set up and read notes for boss fights, watch out people's timers together with many other raid utility tools.
    Friend Groups example image.
    Friend Groups
    Organize your friendlist by groups (like "Guild", "M+", "IRL") that make sense instead of the current mess.
    SexyMap example image.
    Move around, scale and change the aspect of the minimap.
    Allows you to move around any Blizzard's native frame (like quest, character panel, etc) and they'll retain that position in the future.
    Angry Assignments example image.
    Angry Assignments
    Useful for Healers and Tanks in a raid setup, it allows you to set up your healing cooldowns for the upcoming fights and keep in a well organized notes on screen for every healer.
    AdiBags example image.
    Bag management addon with automatic filtering.
    Narcissus example image.
    A nice recap display for your character's gear and stats.
    MBB (Minimap Buttons Bag) example image.
    MBB (Minimap Buttons Bag)
    Groups all those minimap icon buttons into one single place to clean up that space.
    Leatrix Plus
    Utility addon for many things, like auto-repair, auto-sell junk, and about 40 more quality of life improvements you can setup.
    DejaCharacterStats example image.
    Enhance the stats section of your character panel with more meaningful metrics, and allows you to reorganize them too.
    In case you still need combat texts in 2021, there you go. But to be fair, it's a little irrelevant nowadays in PvE, we would recommend to only use Details.