Snuff Out is a huge upgrade against the low-toughness Cat tokens, Guide of Souls, and Ajani, Nacatl Pariah. Every creature they play is nonblack, so it can destroy any of them for free off a Swamp (Bayou or a fetched Swamp) when we need to leave mana up for our own plays. We take two Thoughtseize out and keep one, since this matchup is more about racing and removal than about stripping a single card from their hand, and the life loss adds up against a lifelink deck. Collector Ouphe has no targets since the opponent runs no artifacts in the main deck. Keep Wasteland and Boseiju in to fight their nonbasic lands, especially Karakas, which can bounce our legendary Atraxa or protect their own Ajani and Thalia.