By no means the absolute ideal set but I thought it might be worth listing these since the question has come up quite a few times in Discord.
If you have other favorites, please post them below as I’m always on the lookout!
First of all, here’s my current UI:
This is the base for my UI. It’s not 100% necessary but does add a few nice to haves. It also makes your UI darkmode while still preserving the default style of Warcraft, which I really like.
MoveAnything is used to… move anything. It’s key for placing your stuff where you want to see it or out of the way.
Must have, for me. The other key is that I use all of Luxthos’s amazing WeakAuras. He is a designer by day and makes some really beautiful sets along with excellent videos that explain how to use them.
The best alternative is Plater. In fact, Plater has a lot more options but I prefer the simple interface and setup of Threat Plates. You can install it and it’s good to go. I have customized mine a bit to significantly highlight interrupt opportunities.
Use these in conjunction with Raidbots in order to easily identify the best gear. This deserves a guide to itself, which maybe I’ll write.
I prefer BigWigs over Deadly Boss Mobs but they will both get the job done. The reason I like BigWigs is that I think it looks nicer out of the box. I’m pretty sure you could accomplish the same look with either of them, though.
Remember to get LittleWigs as it has all your Dungeon info which you need for Mythic+.
Details! (Damage Meter)
Another preference. I like Details due to the way it customizes over Recount. YMMV but they’re essentially the same.
I like to have specific favorite mounts per character rather than per account. My Warlock has a different look and feel than my Warrior, for example. So naturally, they need different mount favorites. That’s what this addon does, among lots of other cool things.
Added awesome is that it will tie pets to your mount key so you can always be accessorized and themed.
This addon keeps track of your collections across all characters. This is very useful for knowing if you want to roll on something for a transmog or if you want to mail it to another character.
The biggest downside is that the database is local so if you play #worldofwarcraft on multiple computers then you won’t have all your dataz.
This is by far my go-to addon for leveling but I also use it for so much more. At max level I use it for optimizing rep grinding, professions, dailies, etc. It also has built in dungeon guides that are useful for completing quests in Timewalking.
Note that it is not free.