Sega Master System - Top tier internal development team pumping out the 1980's equivalent of AAA games (even though they were inferior ports of their arcade systems)...even more so then the Big Nintendo at the time.

Genesis - First move towards adults, superior sports games but the Nintendo brand is a beast and as we talked about above, was putting out -excellent- games. On top of athe first real CD system.

Game Gear - the OG PS Vita. Gameboy came out and was the SHIT but a year later gamegear came out and gave you a console experience right in your hands and nobody gave a fuck.

Saturn - Here' there time where it was less about market bad luck then their fucking up. Sega forgot their playbook while Sony photocoppied that bitch and executed it to a tee.

The true king of their lineup?

Dreamcast - But this is where they took that fucking playbook and amped it to 10. Just a great piece of console technology along with the first online. Think about how insane it was that EA left them out to die...and they created the 2k series which was BETTER then EA's own Madden/Live? A system with similar impact/innovation would have won any previous generation before or since...the problem was that it's opponent was the PS2.