I like to rotate through a handful of some standard ones that come with Procreate! These are the ones I use the most by far
Searching around, there’s actually a whole lot of free brushes that can be downloaded to Procreate as well
My favs have been the SPACE pack and FLORA pack, a whole lot of extremely generous artists have free packs compiled, honestly explore around Gumroad and what not to add on to your brush folders!
Plus look into some tutorials on making your own brushes/stamps because they can be LIFESAVERS if you have to draw smth repetitively, or if you need a quick way to slap on your personal watermark!