Nintendo
SEGA
Capcom
Konami
Square
Enix
In that order for the home console market. It's easy to forget now how popular Konami was in that era. Square wasn't quite as big esp in the US as some of those games didn't release over here. They gave us Mystic Quest which sucks. Konami was just slightly edged out by Capcom but Konami was still pumping out hit after hit.
One company that gets forgotten in the modern-day is Hudson. Hudson with the PC Engine. TG16 was a flop in the west but in Japan was a big success with a huge library.
Back then unlike now, it wasn't just 4-5 big publishers. There was a shit ton.
You can list 50 more big publishers at the time. There were more big studios then since they pumped out so many games in short periods of time plus arcades were huge still.
Bite my shiny metal cockpit!
