Forceful Denial

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Counter target spell.

Wavebreak Hippocamp

Whenever you cast your first spell during each opponent's turn, draw a card.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Rewind

Counter target spell. Untap up to four lands.

Ral, Storm Conduit

Whenever you cast or copy an instant or sorcery spell, Ral deals 1 damage to target opponent or planeswalker.
+2: Scry 1.
−2: When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Chemister's Insight

Draw two cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

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.

Pull from Tomorrow

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Temur Battle Rage

Target creature gains double strike until end of turn.
Ferocious — That creature also gains trample until end of turn if you control a creature with power 4 or greater.

Island

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Decaying Time Loop

Discard all the cards in your hand, then draw that many cards.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Desertion

Counter target spell. If an artifact or creature spell is countered this way, put that card onto the battlefield under your control instead of into its owner's graveyard.

Talrand, Sky Summoner

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

Aetherize

Return all attacking creatures to their owner's hand.

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}.

Spell Swindle

Counter target spell. Create X Treasure tokens, where X is that spell's mana value. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Big Score

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Thunderclap Drake

Flying
Instant and sorcery spells you cast cost {1} less to cast.
{2}{U}, Sacrifice this creature: When you next cast an instant or sorcery spell this turn, copy it for each time you've cast your commander from the command zone this game. You may choose new targets for the copies.

Mindsplice Apparatus

Flash
At the beginning of your upkeep, put an oil counter on this artifact.
Instant and sorcery spells you cast cost {1} less to cast for each oil counter on this artifact.

Unexpected Windfall

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Bria, Riptide Rogue

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Other creatures you control have prowess. (If a creature has multiple instances of prowess, each triggers separately.)
Whenever you cast a noncreature spell, target creature you control can't be blocked this turn.

Insidious Will

Choose one —
• Counter target spell.
• You may choose new targets for target spell.
• Copy target instant or sorcery spell. You may choose new targets for the copy.

Hurl into History

Counter target artifact or creature spell. Discover X, where X is that spell's mana value. (Exile cards from the top of your library until you exile a nonland card with that mana value or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Negate

Winged Boots

Equipped creature has flying and ward {4}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)
Equip {1}

Melek, Reforged Researcher

Melek's power and toughness are each equal to twice the number of instant and sorcery cards in your graveyard.
The first instant or sorcery spell you cast each turn costs {3} less to cast.

Storm-Kiln Artist

This creature gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Access Denied

Counter target spell. Create X 1/1 colorless Thopter artifact creature tokens with flying, where X is that spell's mana value.

Mountain

Artistic Refusal

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Choose one or both —
• Counter target spell.
• Draw two cards, then discard a card.

Arcane Bombardment

Whenever you cast your first instant or sorcery spell each turn, exile an instant or sorcery card at random from your graveyard. Then copy each card exiled with this enchantment. You may cast any number of the copies without paying their mana costs.

Lórien Revealed

Draw three cards.
Islandcycling {1} ({1}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)

Summary Dismissal

Exile all other spells and counter all abilities.

Drown in Dreams

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Target player draws X cards.
• Target player mills twice X cards.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Sky Diamond

This artifact enters tapped.
{T}: Add {U}.

Temple of Epiphany

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {R}.

Reinterpret

Counter target spell. You may cast a spell with equal or lesser mana value from your hand without paying its mana cost.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Arcane Signet

Psionic Pulse

Counter target noncreature spell. (Then exile this card. You may cast the creature later from exile.)

Sapphire Dragon

Flying
Whenever this creature attacks or blocks, scry 2.

Sapphire Dragon // Psionic Pulse

Sol Ring

Past in Flames

Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mana Geyser

Add {R} for each tapped land your opponents control.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. This artifact deals 1 damage to you.

Izzet Signet

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Glamdring

Equipped creature has first strike and gets +1/+0 for each instant and sorcery card in your graveyard.
Whenever equipped creature deals combat damage to a player, you may cast an instant or sorcery spell from your hand with mana value less than or equal to that damage without paying its mana cost.
Equip {3}

Confirm Suspicions

Counter target spell.
Investigate three times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Intrude on the Mind

Reveal the top five cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard. Create a 0/0 colorless Thopter artifact creature token with flying, then put a +1/+1 counter on it for each card put into your graveyard this way.

Overwhelming Intellect

Counter target creature spell. Draw cards equal to that spell's mana value.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Mystic Retrieval

Return target instant or sorcery card from your graveyard to your hand.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Unwind

Counter target noncreature spell. Untap up to three lands.

Counterspell

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.

Arcane Denial

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.

Haughty Djinn

Flying
Haughty Djinn's power is equal to the number of instant and sorcery cards in your graveyard.
Instant and sorcery spells you cast cost {1} less to cast.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Whirlwind Denial

For each spell and ability your opponents control, counter it unless its controller pays {4}.