My rats love peas, cooked pasta, canned corn (gmo-free) etc
You can cook quite human-like things for them, as long as they dont have added processed sugar or salt. Like cooked pasta with a drizzle of olive oil, mixed in with canned tuna or salmon.
Yesterday for dinner my rats got cooked rice and quinoa mixed with bits of cooked salmon

Tonight (Im in southern hemisphere, its currently 3am) they got cooked pasta lightly brushed with salmon oil, chopped carrots, peas, shredded fresh kale and chopped boiled egg

They dont always get this kind of dinner haha they are healthy but getting old (20 months) so Im trying to give them nicer and more interesting dinners to perk them up a bit.
In the past also really enjoyed sweet potato mashed with coconut milk, plain coconut milk, oatmeal and baby food (farex baby cereal, softened and 'cooked' with warm liquid)