I've been looking for an app that is good for a long time…
Gimp or Sketchbook pro. Both are free and extensive
I personally use Medibang Paint.
There are not very many brushes there, but in my opinion I think that's a good thing as too many brushes initially make you lose track. You are welcome to try it out
Free: Medibang, Procreate, Autodesk Sketchbook, Mypaint, Ibis Paint,
Not Free: Clip Stidio Paint, Photoshop, SAI