you could get a tiger tail cucumber, black sand-mopping, or the generic cucumber. Those types don't have the "cuke nukes" when they die. And unlike the donkey turds, you can tell.
Porcelain, emerald, and Sally Lightfoot crabs
most hermit crabs
Turban and bumblebee snails
Watchmen Gobies, Engineer Gobies, and orange marked Gobies also make good sand sifters.