Fellwar Stone

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

Dualcaster Mage

Flash
When Dualcaster Mage enters, copy target instant or sorcery spell. You may choose new targets for the copy.

Mana Geyser

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

Mogg Salvage

If an opponent controls an Island and you control a Mountain, you may cast this spell without paying its mana cost.
Destroy target artifact.

Runaway Steam-Kin

Whenever you cast a red spell, if Runaway Steam-Kin has fewer than three +1/+1 counters on it, put a +1/+1 counter on Runaway Steam-Kin.
Remove three +1/+1 counters from Runaway Steam-Kin: Add {R}{R}{R}.

Goblin Matron

When Goblin Matron enters, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

_____ Goblin

When this creature enters, you may put a name sticker on it. Add {R} for each unique vowel on that sticker. (The vowels are A, E, I, O, U, and Y.)

Burnout

Counter target instant spell if it's blue.
Draw a card at the beginning of the next turn's upkeep.

Reckless Barbarian

Sacrifice Reckless Barbarian: Add {R}{R}.

Blood Moon

Red Elemental Blast

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

Wild Ricochet

You may choose new targets for target instant or sorcery spell. Then copy that spell. You may choose new targets for the copy.

Skirk Prospector

Iron Myr

Unexpected Windfall

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 artifact: Add one mana of any color.")

Palladium Myr

Coldsteel Heart

Coldsteel Heart enters tapped.
As Coldsteel Heart enters, choose a color.
{T}: Add one mana of the chosen color.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Arcane Signet

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

Goro-Goro, Disciple of Ryusei

{R}: Creatures you control gain haste until end of turn.
{3}{R}{R}: Create a 5/5 red Dragon Spirit creature token with flying. Activate only if you control an attacking modified creature. (Equipment, Auras you control, and counters are modifications.)

Magus of the Wheel

{1}{R}, {T}, Sacrifice Magus of the Wheel: Each player discards their hand, then draws seven cards.

Soulbright Flamekin

{2}: Target creature gains trample until end of turn. If this is the third time this ability has resolved this turn, you may add {R}{R}{R}{R}{R}{R}{R}{R}.

Seething Song

Sol Ring

Last Chance

Take an extra turn after this one. At the beginning of that turn's end step, you lose the game.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Infernal Plunge

As an additional cost to cast this spell, sacrifice a creature.
Add {R}{R}{R}.

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.

Manakin

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Godo, Bandit Warlord

When Godo, Bandit Warlord enters, you may search your library for an Equipment card, put it onto the battlefield, then shuffle.
Whenever Godo attacks for the first time each turn, untap it and all Samurai you control. After this phase, there is an additional combat phase.

Daretti, Scrap Savant

+2: Discard up to two cards, then draw that many cards.
−2: Sacrifice an artifact. If you do, return target artifact card from your graveyard to the battlefield.
−10: You get an emblem with "Whenever an artifact is put into your graveyard from the battlefield, return that card to the battlefield at the beginning of the next end step."
Daretti, Scrap Savant can be your commander.

Pyretic Ritual

Heiko Yamazaki, the General

Trample
Whenever a Samurai or Warrior you control attacks alone, you may cast target artifact card from your graveyard this turn.

Brass Squire

{T}: Attach target Equipment you control to target creature you control.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Jeweled Amulet

{1}, {T}: Put a charge counter on Jeweled Amulet. Note the type of mana spent to pay this activation cost. Activate only if there are no charge counters on Jeweled Amulet.
{T}, Remove a charge counter from Jeweled Amulet: Add one mana of Jeweled Amulet's last noted type.

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Boil

Diamond Lion

{T}, Discard your hand, Sacrifice Diamond Lion: Add three mana of any one color. Activate only as an instant.

Big Score

Twinflame

Strive — This spell costs {2}{R} more to cast for each target beyond the first.
Choose any number of target creatures you control. For each of them, create a token that's a copy of that creature, except it has haste. Exile those tokens at the beginning of the next end step.

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

Hedron Crawler

{T}: Add {C}. ({C} represents colorless mana.)

Goblin Engineer

When Goblin Engineer enters, you may search your library for an artifact card, put it into your graveyard, then shuffle.
{R}, {T}, Sacrifice an artifact: Return target artifact card with mana value 3 or less from your graveyard to the battlefield.

Ornithopter of Paradise

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)