Crookshank Kobolds

Crookshank Kobolds sees essentially no play in Legacy or Vintage despite being legal in both — free spells are powerful there, but a 1/1 with no text doesn't clear the bar when the competition is Mox Sapphire and Force of Will. Pauper is the only constructed format where zero-mana creatures occasionally appear in combo shells, though Crookshank Kobolds is too underpowered even there. Commander is where it actually finds a home, slotting into specific engines that care about casting zero-cost permanents — primarily Flubs, the Fool builds — where its only relevant characteristic is costing nothing to cast.