Assuming free range, fair chase of course:

1/ Sambar Deer. Anyone who gets a trophy class Sambar without the aid of hounds is a very dedicated and skilled hunter in my book.
2/ Buffalo. Contrary to some opinions, finding a 100 point plus Buffalo is not easy. Finding a 120 plus Buff is even harder. And if you take one on foot from 70 meters or under, or, heaven forbid with a bow, you've earnt your stripes.
3/ Red Deer. Majestic and beautiful animal.
4/ Banteng. Dangerous game species and envy of hunters right round the world. Not many hunters can claim to have got one.
5/ Pigs. Oh they're just dammed good fun.

Gryphon. Believe it or not, folks do go home empty handed after hunting Buff. Not many, but some. I've gone into good Buff country and not found them. They can be dammed elusive at times. On the other hand Chital, or even Fallow in some places, can be comparitively easy to hunt. But like all species be it pigs, goats, deer, Buff or anything, its getting a Big one that is the real hard part.