Change the text of target spell or permanent by replacing all instances of one color word with another. (This effect lasts indefinitely.)
Flashback

Choose one or both —
• Counter target spell.
• Tap one or two target creatures.

Until end of turn, target creature loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Counter target noncreature spell. Its controller creates two Treasure tokens.

Target player draws three cards.

Counter target artifact or enchantment spell.

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Counter target creature or planeswalker spell unless its controller pays . If an opponent has eight or more cards in their graveyard, instead counter that spell, then scry 2.

Up to two target creatures each get +1/+0 until end of turn and can't be blocked this turn. (Then exile this card. You may cast the creature later from exile.)

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

This spell costs less to cast if you control a Wizard.
Draw three cards.

Target creature gets -4/-0 until end of turn.
Learn.

If an opponent searched their library this turn, you may pay rather than pay this spell's mana cost.
Target opponent mills thirteen cards.

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Target permanent becomes an artifact in addition to its other types until end of turn.
Draw a card.

Return target creature to its owner's hand.
Addendum — If you cast this spell during your main phase, draw a card.

Draw two cards. If you control no artifacts, discard a card.

Change the text of target spell or permanent by replacing all instances of one creature type with another. The new creature type can't be Wall. (This effect lasts indefinitely.)

Convoke
Choose one or both —
• Counter target spell.
• Draw two cards, then discard a card.

Until end of turn, target creature gets +1/+3 and gains flying and toxic 1.

As an additional cost to cast this spell, sacrifice an artifact.
Create two tapped Powerstone tokens. Draw a card.

Affinity for artifacts
Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Counter target creature or battle spell unless its controller pays . If they do, you incubate 2.

Attach target Aura you control to target creature.
Draw a card.

Gain control of target Aura that's attached to a permanent. Attach it to another permanent it can enchant.

Choose two —
• Creatures you don't control get -3/-0 until end of turn.
• Create two tapped Powerstone tokens.
• Create a tapped 0/0 colorless Construct artifact creature token with "This creature gets +1/+1 for each artifact you control."
• Scry 2, then draw a card.

Choose one —
• Fight the Current — The owner of target nonland permanent puts it on the top or bottom of their library.
• Find a Crossing — Target creature gets +1/+0 until end of turn and can't be blocked this turn.

Turn target creature with a morph ability face down.
Cycling

Counter target spell, then ask a person outside the game if that spell looks dangerous to them. If they say yes, draw a card, then discard a card.

Counter target spell. If that spell targets a commander you control, instead counter that spell, scry 2, then draw a card.