Sorry, I know this is old, but I couldn't help responding.
There are no hamster breeds. But there are species
Russian Campbell Dwarf (RCD)
Winter White (WW)
No other hamster species can breed together besides RCD+WW's and unfortunately they include lots of health problems as in the wild they never would have found each other to breed together. We don't encourage deliberate breeding of these hybrids, yet it can't be helped as there are many pet mills.
Within these species, there are different fur-colorations, but those aren't referred to as breeds either, just different coats.
Syrians tend to be the most popular species, and have been 'domesticated'* the longest, Chinese hamsters tend to be the climbing species, RCD, WW, and Hybrids tend to be one of the most common dwarf hamsters, and robos tend to be the smallest and most skittish because they haven't been *domesticated as long.
*I'm using the term 'domesticated' loosely as hamsters aren't domesticated as a cat or dog are.