A few of these are more scarce than rare, but here's my list.
On The Ball (SNES) - I'll second Aussie2B on this. I read about it one night in an article here at DP titled "75 games you might have missed" (It's number 44 on the list). I put it on my want list. Shortly after, I found it in a store for $5 and bought it. Pretty glad I did, it's one of my favorite SNES games now. You manipulate the maze to move a ball.
Zero The Kamikaze Squirrel (SNES, Genesis) - A spin-off of the Aero The Acrobat games. Not a bad platformer.
Dino City (SNES) - Highly underrated platformer. You can play as one of two dinosaurs carrying a little kid on their back. The kid can jump off the dinosaur's back to reach places the dinosaur wouldn't be able to alone.
Spanky's Quest (SNES) - The best way I can describe this is as something between Bubble Bobble and Adventures Of Lolo. And for a laugh, the main character is a monkey.
Biker Mice From Mars (SNES) - If you like Super Mario Kart and Rock N Roll Racing, you should enjoy this as well.