i have added sauteed vegetables chopped fine....onions, zucchini, corn,
tomato, olives, green pepper, carrots, mild green chiles. yummy.

black beans take well to a combination of orange juice, chopped fresh
tomatoes, parsley, and minced onions. it's cuban-style, i believe.
these go well with brown rice.

or try mixing into eht beans 1 t of cumin not spicy but very flavorful)
and 1/2 t paprika to perk up your tastebuds.
after heating it., top it with chopped cilantro and chopped green
onions.

guacamole is delicious, but it adds fat.

you can use fat-free cheddar or jack cheese to it, and fat-free sour
cream.

also use salsa; there are mild varietties or you can make a simople one
by mixing a can of tomatoes, a clove of garlic, half an onion, and a
squeeze of lemon or lime juice in a blender or food processor.