Can you help me find the coolest backpack for my 5 year old kindergartener?

I bought him this really cute backpack that looks like a dragon with tongue out and it was green and red and perfect. Now, apparently, it’s too small and he needs something bigger, the teacher says, so that she doesn’t have to fold his folders and books anymore. Can you find me a link to a really cool-looking bag? Please remember..don’t just shop for a boy, I want all kinds of backpacks.