I would call Jim Corbett as a must visit wildlife sanctuary in India. Be stay, be rides it’s great to visit. Another is Kanha national park where I got to see a live tiger. Be the safari ride and green nature, it’s a lovely national park.
This depends on what type of vegetations and flora and fauna you want to experience. Here's a list I feel one should explore: 1. Kaziranga National Park
2. Dehing Patkai National Park
3. Kanha National Park
4. Sundarban
5. Bhitarkanika National Park
6. Dibru Saikhowa National Park
7. Gim Corbett National Park
8. Ranthambore National Park
9. Gir National Park
10. Hemis National Park
11. Satpura National Park
12. Periyar National Park
13. Kangchendzonga National Park
14. Bannerghatta National Park 15. Manas National Park