Razzle-Dazzler

Whenever you cast your second spell each turn, put a +1/+1 counter on this creature. It can't be blocked this turn.

Azorius Guildgate

This land enters tapped.
{T}: Add {W} or {U}.

Second Guess

Counter target spell that's the second spell cast this turn.

Island

Clarion Spirit

Whenever you cast your second spell each turn, create a 1/1 white Spirit creature token with flying.

Uthros Psionicist

The second spell you cast each turn costs {2} less to cast.

Saruman the White

Ward {2}
Whenever you cast your second spell each turn, amass Orcs 2. (Put two +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. This land deals 1 damage to you.

Mystic Skyfish

Whenever you draw your second card each turn, this creature gains flying until end of turn.

Essence Scatter

Negate

Thopter Mechanic

Whenever you draw your second card each turn, put a +1/+1 counter on this creature.
When this creature dies, create a 1/1 colorless Thopter artifact creature token with flying.

Monk of the Open Hand

Flurry of Blows — Whenever you cast your second spell each turn, put a +1/+1 counter on this creature.

Homunculus Horde

Whenever you draw your second card each turn, create a token that's a copy of this creature.

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Knowledge Seeker

Vigilance
Whenever you draw your second card each turn, put a +1/+1 counter on this creature.
When this creature dies, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Lat-Nam Adept

Whenever you draw your second card each turn, put a +1/+1 counter on this creature.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Avatar Yangchen

Flying
Whenever you cast your second spell each turn, airbend up to one other target nonland permanent. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)

The Legend of Yangchen

(As this Saga enters and after your draw step, add a lore counter.)
I — Starting with you, each player chooses up to one permanent with mana value 3 or greater from among permanents your opponents control. Exile those permanents.
II — You may have target opponent draw three cards. If you do, draw three cards.
III — Exile this Saga, then return it to the battlefield transformed under your control.

The Legend of Yangchen // Avatar Yangchen

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Tiger-Seal

Vigilance
At the beginning of your upkeep, tap this creature.
Whenever you draw your second card each turn, untap this creature.

Poised Practitioner

Flurry — Whenever you cast your second spell each turn, put a +1/+1 counter on this creature. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Monologue Tax

Whenever an opponent casts their second spell each turn, you create a Treasure token.

Cosmogrand Zenith

Whenever you cast your second spell each turn, choose one —
• Create two 1/1 white Human Soldier creature tokens.
• Put a +1/+1 counter on each creature you control.

Alisaie Leveilleur

Partner with Alphinaud Leveilleur (When this creature enters, target player may put Alphinaud Leveilleur into their hand from their library, then shuffle.)
First strike
Dualcast — The second spell you cast each turn costs {2} less to cast.

Faerie Vandal

Flash (You may cast this spell any time you could cast an instant.)
Flying
Whenever you draw your second card each turn, put a +1/+1 counter on this creature.

Highspire Bell-Ringer

Flying
The second spell you cast each turn costs {1} less to cast.

Wingblade Disciple

Flying
Flurry — Whenever you cast your second spell each turn, create a 1/1 white Bird creature token with flying.

Mantle of Tides

Equipped creature gets +1/+2.
Whenever you draw your second card each turn, attach this Equipment to target creature you control.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Goldbug, Scrappy Scout

Living metal (During your turn, this Vehicle is also a creature.)
Human spells you control can't be countered.
Whenever Goldbug and at least one Human attack, draw a card and convert Goldbug.

Goldbug, Humanity's Ally

More Than Meets the Eye {W}{U} (You may cast this card converted for {W}{U}.)
Prevent all combat damage that would be dealt to attacking Humans you control.
Whenever you cast your second spell each turn, convert Goldbug.

Goldbug, Humanity's Ally // Goldbug, Scrappy Scout

Annul

Counter target artifact or enchantment spell.

Aligned Heart

Flurry — Whenever you cast your second spell each turn, put a rally counter on this enchantment. Then create a 1/1 white Monk creature token with prowess for each rally counter on it. (Whenever you cast a noncreature spell, the token gets +1/+1 until end of turn.)

Tomb of Horrors Adventurer

When this creature enters, you take the initiative.
Whenever you cast your second spell each turn, copy it. If you've completed a dungeon, copy that spell twice instead. You may choose new targets for the copies. (A copy of a permanent spell becomes a token.)

Shackle Slinger

Whenever you cast your second spell each turn, choose target creature an opponent controls. If it's tapped, put a stun counter on it. Otherwise, tap it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

University Campus

This land enters tapped.
{T}: Add {W} or {U}.
{4}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Plains

Sharlayan, Nation of Scholars

Rammas Echor, Ancient Shield

Whenever you cast your second spell each turn, draw a card, then create a 0/3 white Wall creature token with defender.
At the beginning of combat on your turn, creatures you control with defender gain exalted until end of turn. (Whenever a creature you control attacks alone, it gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

The Council of Four

Whenever a player draws their second card during their turn, you draw a card.
Whenever a player casts their second spell during their turn, you create a 2/2 white Knight creature token.

North Pole Gates

This land enters tapped.
{T}: Add {W} or {U}.
{4}, {T}, Sacrifice this land: Draw a card.

Knights of Dol Amroth

Alphinaud Leveilleur

Partner with Alisaie Leveilleur (When this creature enters, target player may put Alisaie Leveilleur into their hand from their library, then shuffle.)
Vigilance
Eukrasia — Whenever you cast your second spell each turn, draw a card.

Station Monitor

Whenever you cast your second spell each turn, create a 1/1 colorless Drone artifact creature token with flying and "This token can block only creatures with flying."

Wayspeaker Bodyguard

When this creature enters, return target nonland permanent card with mana value 2 or less from your graveyard to your hand.
Flurry — Whenever you cast your second spell each turn, tap target creature an opponent controls.

Oji, the Exquisite Blade

When Oji enters, you gain 2 life and scry 2.
Whenever you cast your second spell each turn, exile up to one target creature you control, then return it to the battlefield under its owner's control.

Doomskar Oracle

Whenever you cast your second spell each turn, you gain 2 life.
Foretell {W} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Prince Imrahil the Fair

Whenever you draw your second card each turn, create a 1/1 white Human Soldier creature token.

Deem Inferior

This spell costs {1} less to cast for each card you've drawn this turn.
The owner of target nonland permanent puts it into their library second from the top or on the bottom.

Syncopate

Counter target spell unless its controller pays {X}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Storm of Saruman

Ward {3}
Whenever you cast your second spell each turn, copy it, except the copy isn't legendary. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Ledger Shredder

Flying
Whenever a player casts their second spell each turn, this creature connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

It'll Quench Ya!

Counter target spell unless its controller pays {2}.

Mirrormind Crown

As long as this Equipment is attached to a creature, the first time you would create one or more tokens each turn, you may instead create that many tokens that are copies of equipped creature.
Equip {2}

Illvoi Operative

Whenever you cast your second spell each turn, put a +1/+1 counter on this creature.

Jace, Arcane Strategist

Whenever you draw your second card each turn, put a +1/+1 counter on target creature you control.
+1: Draw a card.
−7: Creatures you control can't be blocked this turn.

Ethereal Investigator

Flying
When this creature enters, investigate X times, where X is the number of opponents you have. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you draw your second card each turn, create a 1/1 white Spirit creature token with flying.

Minn, Wily Illusionist

Whenever you draw your second card each turn, create a 1/1 blue Illusion creature token with "This token gets +1/+0 for each other Illusion you control."
Whenever an Illusion you control dies, you may put a permanent card with mana value less than or equal to that creature's power from your hand onto the battlefield.

Incursion Specialist

Whenever you cast your second spell each turn, this creature gets +2/+0 until end of turn and can't be blocked this turn.

The Unagi of Kyoshi Island

Flash
Ward—Waterbend {4}. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}. They can tap their artifacts and creatures to help. Each one pays for {1}.)
Whenever an opponent draws their second card each turn, you draw two cards.

Taigam, Master Opportunist

Flurry — Whenever you cast your second spell each turn, copy it, then exile the spell you cast with four time counters on it. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)

Vibrant Cityscape

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Codespell Cleric

Vigilance
When this creature enters, if it was the second spell you cast this turn, put a +1/+1 counter on target creature.

Sunstar Lightsmith

Whenever you cast your second spell each turn, put a +1/+1 counter on this creature and draw a card.

Evolving Wilds

Mangara, the Diplomat

Lifelink
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.
Whenever an opponent casts their second spell each turn, draw a card.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Erudite Wizard

Monk Class

(Gain the next level as a sorcery to add its ability.)
The second spell you cast each turn costs {1} less to cast.
{W}{U}: Level 2
When this Class becomes level 2, return up to one target nonland permanent to its owner's hand.
{1}{W}{U}: Level 3
At the beginning of your upkeep, exile the top card of your library. For as long as it remains exiled, it has "You may cast this card from exile as long as you've cast another spell this turn."

Trouble in Pairs

If an opponent would begin an extra turn, that player skips that turn instead.
Whenever an opponent attacks you with two or more creatures, draws their second card each turn, or casts their second spell each turn, you draw a card.

Crossroads Village

This land enters tapped. As it enters, choose a color.
{T}: Add one mana of the chosen color.

Stalwarts of Osgiliath

When this creature enters, the Ring tempts you.
Whenever you draw your second card each turn, put a +1/+1 counter on this creature.

Alandra, Sky Dreamer

Whenever you draw your second card each turn, create a 2/2 blue Drake creature token with flying.
Whenever you draw your fifth card each turn, Alandra and Drakes you control each get +X/+X until end of turn, where X is the number of cards in your hand.

Lavinia, Foil to Conspiracy

Vigilance
Whenever you cast your second spell each turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{T}: Add {C}{C}. Activate only during an opponent's turn.

Thopter Fabricator

Flying
Whenever you draw your second card each turn, create a 1/1 colorless Thopter artifact creature token with flying.
Crew 2

Thunder Drake

Flying
Whenever you cast your second spell each turn, put a +1/+1 counter on this creature.