There are several breeds of bantam ducks, but the APA recognises east indies, calls, and mallards. The ABA recognises those breeds and mandarins and wood ducks. There are non recognised breeds like mimi appleyards, australian spotted or something like that, and many more that I havent heard of.
I have Calls and East Indies. They are hardy little ducks! They are just like big ducks, except they can fly and you have to worry about more predators than with the bigger ducks. Also, the day olds do not ship well.
They lay seasonally so they are a little more expensive than some of the other breeds that lay all year round. They are also a little harder to hatch and more fragile when shipped.
Another breed is the Silkie duck. I don't know how hardy the other bantams are because I haven't owned any, but I would love to!