Well currently there's just apple and they are super secretive about their roadmap, the M1/2 top line chip already perform quite well, and while the top version look expensive, a pair of a6000 will definitely eat more money both to purchase and to run.

M3 is around the corner tho, and there's some announcement to come from intel or arm following their partnership. There's also the new card coming from intel that is supposed to be aimed squarely at machine learning workloads, and they don't have to segment their market by memory sizing like Nvidia do, but they aren't well supported as device targets, but a pair of these will likely be very cost effective if and only if they will get credible compatibility with the libraries and models