Some of these require a bit more driving from Yountville, but do-able if you are not in a hurry.
Oxbow Public Market - Hog Island oysters (go during happy hour), Ca Momi has some great Italian style desserts/pastries (also a VPN certified pizza place, though if you do pasta/pizza their downtown location is more spacious). A nice way to spend some time in between meals or if you want to snack around instead of a proper sit down meal. You can also get coffee from Ritual and ice cream from Three Twins in the same area.
Redd Wood - decent pizza and pasta
Bistro Jeanty - Favorite French Bistro in all of Northern California. Tomato soup in puff pastry, escargot, house baguette, bone marrow in Bordelaise sauce, salad Nicoise, onion soup, crispy pork foot (specials only), foie (when they have it on specials black board), Moules Frites. It’s always a must for me when I am in the area
Model Bakery (Saint Helena and next to Fatted Calf in Napa) has some very tasty English muffins and breakfast sandwiches made with English muffins (particularly ones with bacon, egg, cheddar with their signature sauce). Makes for a nice breakfast or snack.
Ninebark - quite a pleasant experience though some dishes worked better than others. Solid cocktails and pretty decent wine and bubbles list
Farmstead at Long Meadow Ranch - very pleased with my lunch visit. Simple things like beet salad and lamb meatballs executed very nicely.
You could look into Meadowood at the bar, for a fraction of the cost.