+Gloom (13)
: Mill a card.
Delirium — At the beginning of your end step, if there are four or more card types among cards in your graveyard, transform Autumnal Gloom.
Douse in Gloom deals 2 damage to target creature and you gain 2 life.
Nonblack creatures get -1/-1 until end of turn.
White spells cost more to cast.
Activated abilities of white enchantments cost more to activate.
Whenever Gloom Sower becomes blocked by a creature, that creature's controller loses 2 life and you gain 2 life.
If combat damage would be dealt to Gloom Surgeon, prevent that damage and exile that many cards from the top of your library.
Flying
Threshold — As long as seven or more cards are in your graveyard, Gloomdrifter has "When Gloomdrifter enters the battlefield, nonblack creatures get -2/-2 until end of turn."
Destroy target creature. If that creature was green or white, its controller discards a card.
Reach
Gloomwidow can block only creatures with flying.
Destroy target creature with flying. If that creature was blue or black, create a 1/2 green Spider creature token with reach. (It can block creatures with flying.)
Reach (This creature can block creatures with flying.)
Wither (This deals damage to creatures in the form of -1/-1 counters.)