What are healthy toppings to put on plain beans or oats?

Coconut oil is. excellent if you like the taste. Also consider tomato sauce or paste, just make sure it is free of added sugar, better yet make your own. Use herbs from the garden or dried, such as oregano,basil, parsley, etc. Peace and good health.Try fresh fruit w/oats.
Salsa,guac/berries. Salsa is popular with beans for a reason and there are health benefits to hot peppers. Avocado/guacamole is very healthy and can also be added, and I like to add onions (or mix in onions as they cook). As Dr. Seif mentions,various herbs can also be added. For oats I recommend nuts (walnuts, almonds & pecans),seeds such as hemp or flax seeds,berries (esp. blueberries) &/or yogurt (ideally organic).