I have seen:
Lion: RMNP on Deer Mountain and just beyond Lawn Lake
Black Bear: RMNP on McGregor Mountain(probably 10 times) and Fern Lake Trail
Bobcat: Longs Peak trail, and on some trail just outside of Ouray.
and of course elk, moose,bighorn, mule deer, marmot, pika, fox, martin,etc....
I think some of the only animals I have yet to see are beavers and mountain goats.