New animations can be created upon new phenotypes. It can be quite a process.
See the work by NinjaweaselMan, Ragnarok and Vaei <more> Also Barrel/carpet phenotypes, climbing and horses too.
Creature animations (Large and small) are much more limited. There are "F" model types but they too are limited by inheritance, like a PC. Some animations are looping and some are "fire and forget", both can be initiated through scripted events...
Because of the "Great and Benign Creators", <pause> ....
the game was expanded to allow for 20 additional custom animations (per phenotype) but they follow a strict nomenclature which splits the animation into a "start" "middle" and "end". All of them can be triggered by varying scripted functions but at present there remains a "stutter" when switching phenotypes. There is an upper limit of 100 (?) phenotypes available to the engine.
Nwn presents many user modifiable attributes that few games since have dared allow.
Does that pique your appetite?