A close relative of the 6502, the 6510 is the CPU inside of the
Commodore 64. It has 3 registers, 256 opcodes (although not all of them are useful), and runs at
around 1 MHz, depending on wether it's in a PAL or NTSC system. I'll spare you the opcode list I thought of pasting here :).
Also related is the 8500, which is used in the C128, and is 2MHz capable.