Welcome to toddlerhood!
Try offering things he's had before but won't eat now in a different form. Serve fruits and veggies in strips instead of cubes if he has enough teeth to bite pieces off. Dd started balking about eating some fresh fruit, but she will eat canned peaches and pears. If he won't eat oatmeal (and oatmeal made thick can be a finger food), try oatmeal breakfast bars (this is on my list of foods to try with dd).
Also, if you're into cooking at all, try making fruit or vegetable breads. Dd loves banana bread. In fact, she had banana bread and cream cheese for lunch. I've heard pumpkin muffins go over well too (also on my list to try).
I also buy mixed frozen veggies, so when I make veggies for dinner she has several to choose from. Hopefully, she'll eat one of them.
In general, though, I feed dd kid-friendly age-appropriate stuff for breakfast (cereal, pancakes, waffles, toast, fruit, etc) and lunch (grilled cheese, quesadillas, lunchmeat and cheese, thick soup with the broth strained off, random leftovers). Dh and I make it a point to sit down together as a family for dinner, and she gets whatever we're having. It's always stuff she can have, but sometimes she eats, and sometimes she doesn't. I try not to sweat it. I figure if she's hungry, she'll eat, and I want her to get used to eating what we eat.