One of the essential mods in my collection would have to be Fair Skin Complexion from Nexus Mods

 

https://www.nexusmods.com/skyrimspecialedition/mods/798

 

Not only does it handle the skin textures of my models' bodies, it actually applies a new but subtle makeover to the faces of most females in the vanilla game.  This is great because with the majority of downloadable followers you know what you're getting; finding new potential photo shoot subjects basically at random as I've explored Skyrim has been enjoyable.  

 

It's a good place to start with follower mods IMO because it gives you a new standard of what "beauty" can possibly be in the game, before you start adding followers intentionally designed to be attractive.  

 

It made the look of this character possible, along with a few other NPCs I plan to feature here in the future (original appearance spoiler)