NCF – Extended list of Neutral creatures.

They look great! Could you tell me if it's possible to create models with animations from other games? Disciples 3, King's Bounty...? How feasible is that?

I don't do model porting; I use models by Hannick (he doesn't mind, and Footman too, but I haven't gotten to his models yet).
In theory, you can add any model; you just need a way to extract it, as well as the skeleton and animations. You can probably find the necessary programs on the forums for those games.
The main thing is to avoid the problems we had with Heroes 6 – there were issues with the animations and skeleton.

Added 17 minutes later
Someone extracted models from WoW, but I don't remember who. You'll have to search the forum.