Artist's Point has excellent appetizers! An entire party of about eight people just had appetizers during our trip a few years ago (we'd eaten an early lunch at 50s Prime Time that day, with shared meals no less, but we were still not hungry for our 7:30 pm ADR at AP). We really loved the appetizers, just perfect for a light meal. Some of us had the famous AP mushroom soup, others had seafood-based appetizers (shrimp, crab cake, mussels...I forget, but they were good), others had meat-based appetizers (I think there was sausage and pate). Everyone paired their first appetizer with a salad, and it was perfect.
Captain's Grille at YC (temporarily moved to BC) also had a good selection. My sister and I had appetizers for our meal just last year...fried shrimp for me and the crab cake for sis. We shared a salad as well.
If you enjoy Asian offerings, Yak and Yeti has the usual pot stickers, egg rolls, and wonton soup, but it also has wok fried green beans, sushi, seared tuna salad, and 'sharable' apps that are also enough for one (like tuna nachos, lettuce cups with minced chicken, and a dim sum basket).
Others have pointed out California Grill's menu, so I'm just seconding...nice selection of flatbreads, 'artisan' tacos, and sushi. Also a selection of salads (not just standard 'house' and 'caesar'), charcuterie, and usually a seafood and meat app or two.
Finally, Raglan Road is another place where several in our party had two apps in lieu of an entree or app and entree. Scottish Egg (though labeled Irish here), crock of pate with bread, sausages and mustard, scallops, baked haddock dip, small plate of ribs, and a rather large selection of salads (again beyond 'house' and 'caesar').
