I would say 266 (angled liner), 217 (blending and outer corner), and
239 (packing on color), 224 (for blending) those are some great basics!
if you want to go a lil more advanced, go for a 219 (pencil brush for lower lash line and detailed crease work), 275 (defined outer corner and highlight color)
I think MAC brushes are great quality, you're gona love em!