Fiddler crabs, emerald crabs, porcelain crabs... those kind of crabs.
As for breeding live food organisms, depends on what your definition of "easy" is. I've never heard of anyone on this particular site doing such, and considering how many of us keep cephs and require live foods, I doubt that it would be a relatively easy task. That's why we pay for our pets foods instead.
Whatever you can provide a proper setup for and afford to feed.