I have a little bit when it comes to graded AFL - I sent some stuff into SGC and they graded. I think graded AFL is pretty slow-moving. I know PSAhave all the select sets though.
I honestly think CGA should become more of a player in graded Aussie rules - the buyers and sellers are all here, and an American grader wouldn't know what AFL is, let alone the cards. Always feels off giving cards to graders that don't know the sets.
For example, in soccer, because there are so many sets out there from all over Europe a fair few counterfeit stickers have been produced and graded by BGS - one sticker in particular. Graders don't know the sets, so it's hard to pick counterfeits. We're obviously nowhere near there being the money to really making counterfeits worth it, but some older VFL cards creep up there in price.