Well as of the current beta there is not a lot in yet, and not that much time left until release so only StarDock could tell you for sure. Hopefully they have a few hundred models they haven't put in yet, but it's looking like we are going to have to wait for the modders to make the kind of variety you are looking for (there are maybe 50 (tops) creature models that I have seen whereas something expansive like UO would typically have hundreds or even thousands). That being said, what they do have in the game is moderate to good quality and fit into the game world well, and StarDock has promised to continue to release new stuff post-launch (which could potentially add to this sum)

Although Frogboy said that a popular joke is that Elemental's budget is less than for the Civ V cut-screens