Be careful with peanut butter, as a glob that is too large can choke a mouse. It's rare though. If you smear the peanut butter on something, it shouldn't ever be an issue.
I give fresh veggie scrap(like if I'm cutting up veggies for dinner, the scrap usually ends up in the rodent bins). Dry pasta is always good and it's cheap. I've also given cooked pasta when I overcook or scorch it cooking, so I tend to give a lot of food waste to the rodents. Dry plain cereals like generic brand cheerios(non-frosted) are also good. Seed treats are almost always snatched up.
Don't over do it though, I have a colony so I can use a lot of scrap since it's scattered through the whole colony.