For retail the only add-on I use is Gathermate2, without loading any community data. And even for Classic for the longest time that’s all I used. Others for Classic like Questie, SellPricePerUnit, a spam blocker / unlimited ignore, have nothing to do with general game play. I even refused to use various threat meters in Classic raiding as a tank. And the role and class doesn’t matter, for them all I’d rather pay attention and react.
I never look up and read or watch any guides. In all games I just go in blind and learn on the go. Pay attention to what is going on and learn and play that way. That has always been my play-style. And even when games nerf dungeons and bosses where they add aoe markers instead of paying attention to boss tells (yes looking at you FFXIV) that just annoys me.
So for me “gameplay” add-ons are just an annoyance, they get in my way and just add clutter to the screen, in my opinion. Part of my annoyance with retail, everything nerfed and lots of clutter. Not that my way is better, but for ME it is.