one piece card game banned cards and Restricted The most recent banlist has

Where Warrant suffers relative to other options is against utility creatures, mainly mana creatures like Llanowar Elves and Incubation Druid, but most control players are happy to see those cards because they can focus their answers on the big threats with little threat of dying from the cheap cards

While not the most ideal, but still possible, you can copy a mana rock like Sol Ring for additional ramp

However, if you do choose a target, and that target is illegal at the time Rat Out tries to resolve, the spell won't resolve and none of its effects will happen

Flying is very common in Commander on Commanders so you'll shutdown the Commander Damage kill option there with this land