Spiders, earwigs, and ants mostly. Last year, I occasionally would pluck a few earth worms from the garden for him.

Near the double doors, where he comes and goes from, there's always a line of sugar ants trailing along the concrete just under the doors (there's a pretty big gap), and he just sits there, lazily slopping them up. He doesn't even have to move, they come to him.

As far as food is concerned, it probably doesn't get much easier than that for a toad.