[Chojin]

the CDI had an expensive 'digital video cartridge' too, and since philips is retarded and let like 9 different people make their system there are different versions of it that work on different systems

intellivision had a speech upgrade

SNES and N64 (memory upgrade and disc drive on the N64) had several hardware expansion ports, as did the PS1

a lot of old consoles did, actually, but they realized in time that that's part of the reason people play games on consoles and not PCs.