I find most actual toys made for hamsters are either the wrong size or badly made. There are a few good products, but you can make some yourself as well
I like Erin's Hamsters 10 toys to make from toilet rolls (added the link below). I think this is a good thing for hamsters too - I've had a couple of them and they're on US Amazon
Amazon.com : Rosewood Naturals Carrot Cottage Hamster House, Small : Pet Supplies
https://www.youtube.com/watch?v=NuPeyD6w-CI