Here's a list of the 10 greatest gimmick shows of all time.

1. Bewitched
2. My Favorite Martian
3. Mister Ed.
4. My Mother the Car
5. The Munsters
6. The Addams Family
7. ALF
8. The Flying Nun
9. Mork and Mindy
10. Baby Talk

If there are any other shows that should be added, please post.

In my top 10, I would replace Baby Talk, My Mother The Car, The Flying Nun and My Favorite Martian with:

1.Gilligan's Island
2. I Dream Of Jeanie
3. Third Rock From The Sun
4. The Beverly Hillbillies

It's tough to expand the category, because if you go to the Hillbillies and Gilligan then Green Acres and the Monkees are right there with them. Sticking to purest fantasy, I'd go with:

1. The Addams Family
2. Mister Ed
3. Alf
4. The Munsters
5. Third Rock from the Sun
6. My Favorite Martian
7. Bewitched
8. My Hero (UK)
9. I Dream of Jeannie
10. Mork and Mindy

Since there's no limitation to Sitcoms, I'd add the original Dark Shadows.

I consider any show that stretches the level of credibility passed the point of believability, to be a gimmick show. Also consider Hogans Heroes as a gimmick show, but it is not in my top 10. If MASH wasn't so heavy on the drama, it would almost fall into the gimmick category for repeating episode tropes and a Korean War that lasted into the beginning of the Vietnam War.