On carts, I would say,
Tempest 2000
Iron Soldier
Val d' Isere Skiing and Snowboarding
Defender 2000 (some don't like this version and prefer Protector SE by Songbird)
and maybe,
Rayman
Raiden
Zool 2
Zoop (good puzzle game)
Pitfall ( I sort-of like this one, not as good as the original)
I like Cybermorph, but I think that is a matter of taste and what one enjoys in gaming.
I have read that Super Burnout is a very good game if you like Super Hang On. I have yet to pick one up. I am going to purchase one in the future when the cash and availability matches up.
Skyhammer and Protector SE, from what I understand, are both must have games. Both are by Songbird.
I don't have the CD-rom drive, so I can't really say concerning those games.