to complete Atari: 2600, 5200, 7800 and Lynx.
SNK = NeoGeo (& NeoGeo CD), NeoGeo Pocket and NeoGeo pocket color.
WonderSwan is a Bandai product...
Sega: Add Master System and 32X.
Nec: PC-Engine and it's spin offs. I must admit that I don't know them all..
Panasonic: 3DO.