Roots of Wisdom Again they are working these insurance policies into cards, so you get to mill, you get to return a land or elf, then if you can't (not choose not to) you get to draw instead
Commander : Even if I don't plan on using a ton of Aetherdrift cards, I've been including Muraganda Raceway in my builds
But for Constructed, it's harder to gauge
Granted, there are a handful of artifact decks around in Modern that Cover of Darkness won't play nicely against
For example, if you control Arcee, Acrobatic Coupe and March of the Machines, Arcee will be a 2/2 artifact creature during your turn and a 3/3 artifact creature (because its mana value is 3) during each opponent's turn
For three mana, everything is protected