Any generic numpad + remapping its keys will work, there's plenty at amazon. I found mines at the thrift store for $2 and works fantastic :D

I grew up with PCs, so I got to play PC ports of Sonic games and R2 & 3. It was definitely a much darker fantasy world with unique characters and inspo from european fairy folklore. Loved game gfx & concepts in R3, land of livid dead was so so cool. Sad there's no intention of returning to 3D :(