Awakened Awareness

Enchant artifact or creature
When Awakened Awareness enters the battlefield, put X +1/+1 counters on enchanted permanent.
As long as enchanted permanent is a creature, it has base power and toughness 1/1.

Sol Ring

Shore Keeper

{7}{U}, {T}, Sacrifice Shore Keeper: Draw three cards.

Common Courtesy

Whenever a player casts a spell without asking your permission while casting it, counter that spell.
When a player asks you permission to cast a spell and you refuse, counter that spell and sacrifice Common Courtesy.

Skyreach Manta

Sunburst (This enters the battlefield with a +1/+1 counter on it for each color of mana spent to cast it.)
Flying

Solve the Equation

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Leveler

When Leveler enters the battlefield, exile all cards from your library.

Aura of Dominion

Enchant creature
{1}, Tap an untapped creature you control: Untap enchanted creature.

So Tiny

Flash
Enchant creature
Enchanted creature gets -2/-0. It gets -6/-0 instead as long as its controller has seven or more cards in their graveyard.

Counterspell

Stone Golem

Golem Artisan

{2}: Target artifact creature gets +1/+1 until end of turn.
{2}: Target artifact creature gains your choice of flying, trample, or haste until end of turn.

Chant of the Skifsang

Enchant creature
Enchanted creature gets -13/-0.

Burnished Hart

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

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Carry Away

Enchant Equipment
When Carry Away enters the battlefield, unattach enchanted Equipment.
You control enchanted Equipment.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Eidolon of Philosophy

{6}{U}, Sacrifice Eidolon of Philosophy: Draw three cards.

Chrome Replicator

When Chrome Replicator enters the battlefield, if you control two or more nonland, nontoken permanents with the same name as one another, create a 4/4 colorless Construct artifact creature token.

Rookie Mistake

Until end of turn, target creature gets +0/+2 and another target creature gets -2/-0.

Ancestral Recall

Cobbled Lancer

As an additional cost to cast this spell, exile a creature card from your graveyard.
{3}{U}, Exile Cobbled Lancer from your graveyard: Draw a card.

Coral Reef

Coral Reef enters the battlefield with four polyp counters on it.
Sacrifice an Island: Put two polyp counters on Coral Reef.
{U}, Tap an untapped blue creature you control, Remove a polyp counter from Coral Reef: Put a +0/+1 counter on target creature.

Boomerang

Return target permanent to its owner's hand.

Island

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Fowl Play

Enchant creature
Enchanted creature loses all abilities and is a Bird creature with base power and toughness 1/1.

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Gearsmith Prodigy

Gearsmith Prodigy gets +1/+0 as long as you control an artifact.

Heliophial

Sunburst (This enters the battlefield with a charge counter on it for each color of mana spent to cast it.)
{2}, Sacrifice Heliophial: It deals damage equal to the number of charge counters on it to any target.

Guardians of Koilos

When Guardians of Koilos enters the battlefield, you may return another target historic permanent you control to its owner's hand. (Artifacts, legendaries, and Sagas are historic.)

Thassa's Oracle

When Thassa's Oracle enters the battlefield, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Staunch Throneguard

Vigilance
When Staunch Throneguard enters the battlefield, you become the monarch.

Phase Dolphin

Whenever Phase Dolphin attacks, another target attacking creature can't be blocked this turn.

Worn Powerstone

Worn Powerstone enters the battlefield tapped.
{T}: Add {C}{C}.

Drifter il-Dal

Shadow (This creature can block or be blocked by only creatures with shadow.)
At the beginning of your upkeep, sacrifice Drifter il-Dal unless you pay {U}.

Larder Zombie

Defender
Tap three untapped creatures you control: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Arcane Signet

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

Floodhound

{3}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Adaptive Shimmerer

Flash
Adaptive Shimmerer enters the battlefield with three +1/+1 counters on it.

Richard Garfield, Ph.D.

You may play cards as though they were other cards of your choice with the same mana cost. You can't choose the same card twice. (Mana cost includes color.)

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Johnny, Combo Player

{4}: Search your library for a card, put that card into your hand, then shuffle.

Gearsmith Guardian

Gearsmith Guardian gets +2/+0 as long as you control a blue creature.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Hedron Archive: Draw two cards.

Present Arms

Exchange your library with another deck you own from outside the game. Shuffle your library.

Decorated Knight

Whenever Decorated Knight attacks, draw a card from your original deck if it's outside the game.

Decorated Knight // Present Arms

Prizefighter Construct

Clockwork Hydra

Clockwork Hydra enters the battlefield with four +1/+1 counters on it.
Whenever Clockwork Hydra attacks or blocks, remove a +1/+1 counter from it. If you do, Clockwork Hydra deals 1 damage to any target.
{T}: Put a +1/+1 counter on Clockwork Hydra.

Rules Lawyer

State-based actions don't apply to you or other permanents you control. (You don't lose the game due to having 0 or less life or drawing from an empty library. Your creatures aren't destroyed due to damage or deathtouch and aren't put into a graveyard due to having 0 or less toughness. Your planeswalkers aren't put into a graveyard if they have 0 loyalty. You don't put a legendary permanent into a graveyard if you control two with the same name. Counters aren't removed from your permanents due to game rules. Permanents you control attached or combined illegally remain on the battlefield. For complete rules and regulations, see rule 704.)

Sky Diamond

Sky Diamond enters the battlefield tapped.
{T}: Add {U}.

Reservoir Walker

When Reservoir Walker enters the battlefield, you gain 3 life and get {E}{E}{E} (three energy counters).

Zulaport Duelist

Flash
When Zulaport Duelist enters the battlefield, up to one target creature gets -2/-0 until end of turn. Its controller mills two cards. (They put the top two cards of their library into their graveyard.)