Which units in the Orc city do you like the most in terms of their appearance?

It seems the design of the unenhanced goblins was likely taken from "The Lord of the Rings."

No, most likely, it was "taken" from Dark Messiah, as it is the only creature in Heroes that resembles its counterpart from DoMM. As for "The Lord of the Rings," Tolkien first described creatures like orcs in his works, and in his stories, the word "orc" was synonymous with the word "goblin," and in general, he laid the foundation for these fantasy creatures, and they often resemble each other in various games and films, having common features when described in literary works, although, specifically in goblins, I don't see any similarity. Perhaps, very remotely.