Ixidor, Reality Sculptor

Face-down creatures get +1/+1.
{2}{U}: Turn target face-down creature face up.

Ashnod's Altar

Counterspell

Thieving Amalgam

At the beginning of each opponent's upkeep, you manifest the top card of that player's library. (Put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)
Whenever a creature you control but don't own dies, its owner loses 2 life and you gain 2 life.

Champion of Lambholt

Creatures with power less than Champion of Lambholt's power can't block creatures you control.
Whenever another creature you control enters, put a +1/+1 counter on Champion of Lambholt.

Branching Evolution

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

Forest

Reyhan, Last of the Abzan

Reyhan, Last of the Abzan enters with three +1/+1 counters on it.
Whenever a creature you control dies or is put into the command zone, if it had one or more +1/+1 counters on it, you may put that many +1/+1 counters on target creature.
Partner (You can have two commanders if both have partner.)

Greater Good

Sacrifice a creature: Draw cards equal to the sacrificed creature's power, then discard three cards.

Mountain

Yedora, Grave Gardener

Whenever another nontoken creature you control dies, you may return it to the battlefield face down under its owner's control. It's a Forest land. (It has no other types or abilities.)

Brine Elemental

Morph {5}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Brine Elemental is turned face up, each opponent skips their next untap step.

Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Become Anonymous

Exile target nontoken creature you own and the top two cards of your library in a face-down pile, shuffle that pile, then cloak those cards. They enter tapped. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Skirk Alarmist

Haste
{T}: Turn target face-down creature you control face up. At the beginning of the next end step, sacrifice it.

Kadena's Silencer

When Kadena's Silencer is turned face up, counter all abilities your opponents control.
Megamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)

Grim Haruspex

Morph {B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
Whenever another nontoken creature you control dies, draw a card.

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Panoptic Projektor

{T}: The next face-down creature spell you cast this turn costs {3} less to cast.
If turning a face-down permanent face up causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Yarus, Roar of the Old Gods

Other creatures you control have haste.
Whenever one or more face-down creatures you control deal combat damage to a player, draw a card.
Whenever a face-down creature you control dies, return it to the battlefield face down under its owner's control if it's a permanent card, then turn it face up.

Kami of Whispered Hopes

If one or more +1/+1 counters would be put on a permanent you control, that many plus one +1/+1 counters are put on that permanent instead.
{T}: Add X mana of any one color, where X is Kami of Whispered Hopes's power.

Roshan, Hidden Magister

Other creatures you control are Assassins in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
Face-down creatures you control have menace.
Whenever a permanent you control is turned face up, you draw a card and you lose 1 life.

Arcane Signet

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

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Ainok Survivalist

Megamorph {1}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Ainok Survivalist is turned face up, destroy target artifact or enchantment an opponent controls.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Frontier Bivouac

Frontier Bivouac enters tapped.
{T}: Add {G}, {U}, or {R}.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Scroll of Fate

{T}: Manifest a card from your hand. (Put that card onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Tin Street Gossip

Vigilance
{T}: Add {R}{G}. Spend this mana only to cast face-down spells or to turn creatures face up.

They Came from the Pipes

When They Came from the Pipes enters, manifest dread twice. (To manifest dread, look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Whenever a face-down creature you control enters, draw a card.

Stomping Ground

({T}: Add {R} or {G}.)
As Stomping Ground enters, you may pay 2 life. If you don't, it enters tapped.

Ketria Triome

({T}: Add {G}, {U}, or {R}.)
Ketria Triome enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Vesuvan Shapeshifter

As Vesuvan Shapeshifter enters or is turned face up, you may choose another creature on the battlefield. If you do, until Vesuvan Shapeshifter is turned face down, it becomes a copy of that creature, except it has "At the beginning of your upkeep, you may turn this creature face down."
Morph {1}{U}

Kraum, Ludevic's Opus

Flying, haste
Whenever an opponent casts their second spell each turn, draw a card.
Partner (You can have two commanders if both have partner.)

Verdant Catacombs

{T}, Pay 1 life, Sacrifice Verdant Catacombs: Search your library for a Swamp or Forest card, put it onto the battlefield, then shuffle.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Grumgully, the Generous

Each other non-Human creature you control enters with an additional +1/+1 counter on it.

Animar, Soul of Elements

Protection from white and from black
Whenever you cast a creature spell, put a +1/+1 counter on Animar, Soul of Elements.
Creature spells you cast cost {1} less to cast for each +1/+1 counter on Animar.

Swamp

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

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.")

Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Abhorrent Oculus

As an additional cost to cast this spell, exile six cards from your graveyard.
Flying
At the beginning of each opponent's upkeep, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Fortune Thief

Damage that would reduce your life total to less than 1 reduces it to 1 instead.
Morph {R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Vannifar, Evolved Enigma

At the beginning of combat on your turn, choose one —
• Cloak a card from your hand. (Put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)
• Put a +1/+1 counter on each colorless creature you control.

Dark Ritual

Renata, Called to the Hunt

Renata's power is equal to your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Each other creature you control enters with an additional +1/+1 counter on it.

Overgrown Tomb

({T}: Add {B} or {G}.)
As Overgrown Tomb enters, you may pay 2 life. If you don't, it enters tapped.

Kheru Spellsnatcher

Morph {4}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Kheru Spellsnatcher is turned face up, counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard. You may cast that card without paying its mana cost for as long as it remains exiled.

Bane of the Living

Morph {X}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Bane of the Living is turned face up, all creatures get -X/-X until end of turn.

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Wooded Foothills

{T}, Pay 1 life, Sacrifice Wooded Foothills: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Skittering Cicada

Flash
You may cast colorless spells as though they had flash.
Whenever you cast a colorless spell, until end of turn, Skittering Cicada gains trample and gets +X/+X, where X is that spell's mana value.

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Scalding Tarn

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Boltbender

Disguise {1}{R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When Boltbender is turned face up, you may choose new targets for any number of other spells and/or abilities.

Rattleclaw Mystic

{T}: Add {G}, {U}, or {R}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Rattleclaw Mystic is turned face up, add {G}{U}{R}.

Stratus Dancer

Flying
Megamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Stratus Dancer is turned face up, counter target instant or sorcery spell.

Secret Plans

Face-down creatures you control get +0/+1.
Whenever a permanent you control is turned face up, draw a card.

Command Tower

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.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Ashcloud Phoenix

Flying
When Ashcloud Phoenix dies, return it to the battlefield face down under your control.
Morph {4}{R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Ashcloud Phoenix is turned face up, it deals 2 damage to each player.

Hauntwoods Shrieker

Whenever Hauntwoods Shrieker attacks, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
{1}{G}: Reveal target face-down permanent. If it's a creature card, you may turn it face up.

Den Protector

Creatures with power less than Den Protector's power can't block it.
Megamorph {1}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Den Protector is turned face up, return target card from your graveyard to your hand.

Kozilek, the Broken Reality

When you cast this spell, up to two target players each manifest two cards from their hands. For each card manifested this way, you draw a card. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)
Other colorless creatures you control get +3/+2.

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Commander's Sphere

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

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Breeding Pool

({T}: Add {G} or {U}.)
As Breeding Pool enters, you may pay 2 life. If you don't, it enters tapped.

Kadena, Slinking Sorcerer

The first face-down creature spell you cast each turn costs {3} less to cast.
Whenever a face-down creature you control enters, draw a card.

Missy

Whenever another nonartifact creature dies, return it to the battlefield under your control face down and tapped. It's a 2/2 Cyberman artifact creature.
At the beginning of your end step, each opponent faces a villainous choice — Each artifact creature you control deals 1 damage to that opponent, or you draw a card and chaos ensues.

Pyrotechnic Performer

Disguise {R} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
Whenever Pyrotechnic Performer or another creature you control is turned face up, that creature deals damage equal to its power to each opponent.

Reliquary Tower

Xander's Lounge

({T}: Add {U}, {B}, or {R}.)
Xander's Lounge enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Island

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.