Hmmm...you could do a yearly blood panel (optional), dental check (visual), palpate the abdomen, listen to heart/lungs, check knees, look into eyes w/ the light "thingy", look into ears. Some people even do yearly organ screens - but I don't think I'll do those unless I think something is wrong or until they're seniors.
I can't think of anything else right off the top of my head....