Choose up to X target creatures. Switch their power and toughness until end of turn.
All creatures get -3/-3 until end of turn.

Flying, ward {1}
Whenever you cast an instant or sorcery spell, mill a card. Return an instant or sorcery card milled this way to your hand. If you can't, put a +1/+1 counter on Covetous Frostwyrm.

Gain control of target permanent. Untap it. It gains haste until end of turn.

The next spell you cast this turn may be cast as though it had flash. When you cast that spell, copy it. You may choose new targets for the copy.
Flashback {3}{U}{U}

[+1]: Crux deals 1 damage to target player or planeswalker. Put a chain counter on up to one target artifact or nonbasic land. It loses all abilities except mana abilities as long as it has a chain counter on it.
[–2]: Discard a card. When you do, Crux deals damage equal to the discarded card's mana value to up to one target creature and you draw a card.
[–6]: Exile target red instant or sorcery card from your graveyard. Add {R}{R}{R}, then you get an emblem with “You may cast copies of the exiled card.”

When Cryptolabe enters, exile your hand and the top card of your library. You may play cards exiled this way for as long as they remain exiled.
{T}: Add {G}{U}. This mana can't be spent to cast spells from your hand.

As an additional cost to cast this spell, exile a card from your graveyard.
Search your library for a card with the same mana value as the exiled card, reveal it, put it into your hand, then shuffle. You lose 2 life.

Deathtouch
Ward—Pay 4 life.
Whenever Cybele of the Frozen Faith deals combat damage to a player, you may skip your next turn. If you do, at the beginning of your next turn's upkeep, each opponent discards their hand, you draw seven cards, then put seven +1/+1 counters on Cybele.

Untap all lands you control. Until end of turn, they become 1/1 Elemental artifact creatures with vigilance, indestructible, and haste in addition to their other types.

Return target permanent card with an activated ability from your graveyard to the battlefield. You may activate its abilities this turn as though it had haste.

When Data Weaver enters, integrate the top two cards of target opponent's library.
Once during each of your turns, you may play a card integrated onto a permanent you control, and mana of any type can be spent to cast it.

Exile all creatures and all cards from each player's hand. Any player may play those cards during their turn for as long as they remain exiled, and mana of any type can be spent to cast those spells.
Exile Dawn of Peace.

Ward {2}
At the beginning of your upkeep, put a +1/+1 counter on Decavolt Reactor.

You may cast this spell as though it had flash by sacrificing a creature in addition to its other costs. If you do, when it enters, attach it to target creature you control.
Equipped creature gets +2/+0 and has “Whenever this creature deals combat damage to a player, that player discards a card.”
Equip—Pay 2 life.

Enchant creature
You control enchanted creature.
Enchanted creature has decayed.

Create a 1/1 colorless Construct artifact creature token, then put a +1/+1 counter on each Construct you control.

When Demographer enters, draw a card, then discard a card. When you discard a nonland card this way, make a pledge.
{2}, {T}: Draw a card, then discard a card. When you discard a nonland card this way, make a pledge.

Depths Ancient's power and toughness are each equal to the number of cards in your graveyard plus the number of exiled cards you own with surface.
Surface {5}{B}{B}

When Desolate Lands enters and whenever you cast a spell, it deals 3 damage to target opponent unless they sacrifice a permanent.

Whenever one or more creatures you control deal combat damage to a player, you draw a card unless that player discards a card.
{X}: Creatures with power X or less can't block this turn. X can't be 0.

Whenever Devourer of Fortunes enters or attacks, return up to one target instant or sorcery card in a graveyard or creature on the battlefield to its owner's hand. You may cast a copy of it, and may spend mana of any type to cast it.

Dhante's Inferno deals 4 damage to any target. Create a number of tapped Treasure tokens equal to the amount of excess damage dealt this way.
{X}, Exile Dhante's Inferno from your graveyard: Each opponent loses X life and you gain X life. Spend only mana from artifact sources to activate this ability. Activate only as a sorcery.

When Diamond Dust enters and whenever you cast a spell, put a +1/+1 counter on each creature you control.

{T}: Add three mana of different colors.

{2}{U}{U}, Exile Digitize the Analog World from your hand: At the beginning of your next upkeep, you may cast Digitize the Analog World from exile without paying its mana cost. Activate only as a sorcery.
Return all nonartifact, nonland permanents to their owner's hands.