Draugr
Bandits
Bears
Trolls
Falmer
Dwemer Machine
Wolf
Vampire
and those are the ones I can remember with 15secs of thinking. The caves are very well done. I agree that they are linear but I don't see that as a problem and there is hand placed loot it is just useless in comparison to smithed items you can make at higher levels by making iron daggers.
I like how "wolf" and "vampire" are considered different tilesets by your standards
Honestly though, they may look different, but 90% of dungions play exactly the same as each other. That's the big problem. A cave may look like a cave but it plays like Drauger, forts, etc. There's no uniqueness to the actual locations/dungions beyond the visual side of things with only a small handful of exceptions.