Ms. Pac-Man is a great one indeed. I have that for my Genesis.
Also on my Genesis, I had the Aladdin game, which was awesome, though I always had serious issues with the lava level. I loved it though; the secrets were fun, and it was a good platformer. I also got it free from my cousin when he didn't want it anymore, so that's nice. Also, the game based on the movie The Pagemaster was a ton of fun. Where else can you throw squishy eyeballs at flying books, bounce on pirates, and dodge literary icons while searching for the exit (and a few library cards along the way). An awesome game based on an awesome movie based on an awesome book based on an awesome concept.
Another one I remember, and have played through to the point where, even now, many years since I've touched it, I'd still know most if not all levels, is Super Mario Land 2: 6 Golden Coins. Now that was a fun game. Fire flowers were awesome, and the bunny ears of flight and glory were pretty sweet.