Not all have any float. As mentioned, it's determined by the cleat (at least in Shimano's system). Actually, I'm not sure about SPD. But with SPD-SL, there are red cleats with zero degrees, blue with 2 or 3 degrees I think, and yellow with 5 degrees. Are you looking specifically at SPD? If so, please disregard my (irrelevant) info.

If you want a clipless pedal with lots of float--and adjustable float range too--you want Wahoos, the model that used to be called Speedplay Zero.