Decisive Denial

Choose one —
• Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)
• Counter target noncreature spell unless its controller pays {3}.

Mystic Confluence

Choose three. You may choose the same mode more than once.
• Counter target spell unless its controller pays {3}.
• Return target creature to its owner's hand.
• Draw a card.

Quandrix Command

Choose two —
• Return target creature or planeswalker to its owner's hand.
• Counter target artifact or enchantment spell.
• Put two +1/+1 counters on target creature.
• Target player shuffles up to three target cards from their graveyard into their library.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Sublime Epiphany

Choose one or more —
• Counter target spell.
• Counter target activated or triggered ability.
• Return target nonland permanent to its owner's hand.
• Create a token that's a copy of target creature you control.
• Target player draws a card.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Confounding Riddle

Choose one —
• Look at the top four cards of your library. Put one of them into your hand and the rest into your graveyard.
• Counter target spell unless its controller pays {4}.

Thassa's Intervention

Choose one —
• Look at the top X cards of your library. Put up to two of them into your hand and the rest on the bottom of your library in a random order.
• Counter target spell unless its controller pays twice {X}.

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Riku of Many Paths

Whenever you cast a modal spell, choose up to X, where X is the number of times you chose a mode for that spell —
• Exile the top card of your library. Until the end of your next turn, you may play it.
• Put a +1/+1 counter on Riku. It gains trample until end of turn.
• Create a 1/1 blue Bird creature token with flying.