Hydrolash

Attacking creatures get -2/-0 until end of turn.
Draw a card.

Dissipate

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

Mountain

Guttersnipe

Whenever you cast an instant or sorcery spell, this creature deals 2 damage to each opponent.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Aetherize

Return all attacking creatures to their owner's hand.

Island

Downsize

Target creature you don't control gets -4/-0 until end of turn.
Overload {2}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Counterspell

Flashfreeze

Negate

Opportunity

Prism Ring

As Prism Ring enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.