Mine are all such munchers I've not had a picky eater yet, so can only share what I do feed them. They all have Harry Hamster through their entire lives as that has suited mine the best, I also scatter meal worms once a week, and they always have a sprig of millet on the go.
For extras they will often get a little of what I'm having, so broccoli, kale, peas, or green beans a couple of times a week, rice, pasta, a little piece if wholemeal pitta, egg ect. They get about one yog drop a week, and a couple of raisins
