The only Aolan forms I've used is Grimer and Marowak.

I used Grimer at the start of my play through of Moon.
I think I replaced it with a female Salandit because I wanted a fire coverage.

I use Marowak as my false swiper for catching Pokémon in Moon.
In Sun Marowak is on my main team.
I'm slightly disgruntled that I can't get some of his better moves until the very end of the game.