Morph/Disguise 

Essence of Antiquity

Disguise {2}{W} (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 this creature is turned face up, creatures you control gain hexproof until end of turn. Untap them.

Ramp

Krosan Wayfarer

Sacrifice this creature: You may put a land card from your hand onto the battlefield.

Llanowar Elves

Cost Reduction

Helm of Awakening

Vesuvan Shapeshifter

As this creature enters or is turned face up, you may choose another creature on the battlefield. If you do, until this creature 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}

Draw Engines

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Force Flip

Zimone, Mystery Unraveler

Landfall — Whenever a land you control enters, manifest dread if this is the first time this ability has resolved this turn. Otherwise, you may turn a permanent you control face up. (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.)

Kadena's Silencer

When this creature 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.)

Overgrown Zealot

{T}: Add one mana of any color.
{T}: Add two mana of any one color. Spend this mana only to turn permanents face up.

Utility

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.)

Den Protector

Creatures with power less than this creature'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 this creature is turned face up, return target card from your graveyard to your hand.

Soul of the Harvest

Trample
Whenever another nontoken creature you control enters, you may draw a card.

Sylvok Explorer

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

Volo, Guide to Monsters

Whenever you cast a creature spell that doesn't share a creature type with a creature you control or a creature card in your graveyard, copy that spell. (A copy of a creature spell becomes a token.)

Glitch Interpreter

When this creature enters, if you control no face-down permanents, return this creature to its owner's hand and manifest dread.
Whenever one or more colorless creatures you control deal combat damage to a player, draw a card.

Daru Sanctifier

Morph {1}{W} (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 this creature is turned face up, destroy target enchantment.

Land

Forest

Primordial Sage

Whenever you cast a creature spell, you may draw a card.

Clifftop Lookout

Reach
When this creature enters, reveal cards from the top of your library until you reveal a land card. Put that card onto the battlefield tapped and the rest on the bottom of your library in a random order.

Dream Chisel

Face-down creature spells you cast cost {1} less to cast.

Mystic Forge

You may look at the top card of your library any time.
You may cast artifact spells and colorless spells from the top of your library.
{T}, Pay 1 life: Exile the top card of your library.

Semblance Anvil

Imprint — When this artifact enters, you may exile a nonland card from your hand.
Spells you cast that share a card type with the exiled card cost {2} less to cast.

Exit Specialist

This creature can't be blocked by creatures with power 3 or greater.
Disguise {1}{U} (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 this creature is turned face up, return another target creature to its owner's hand.

Nantuko Vigilante

Morph {1}{G} (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 this creature is turned face up, destroy target artifact or enchantment.

Hauntwoods Shrieker

Whenever this creature 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.

Chulane, Teller of Tales

Vigilance
Whenever you cast a creature spell, draw a card, then you may put a land card from your hand onto the battlefield.
{3}, {T}: Return target creature you control to its owner's hand.

Voidmage Apprentice

Morph {2}{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 this creature is turned face up, counter target spell.

Nylea, Keen-Eyed

Indestructible
As long as your devotion to green is less than five, Nylea isn't a creature.
Creature spells you cast cost {1} less to cast.
{2}{G}: Reveal the top card of your library. If it's a creature card, put it into your hand. Otherwise, you may put it into your graveyard.

Exotic Orchard

Wilderness Reclamation

At the beginning of your end step, untap all lands you control.

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.

Plant Tadpoles

Tap X target creatures. They don't untap during their controllers' next untap steps. (Then exile this card. You may cast the creature later from exile.)

Illithid Harvester

Ceremorphosis — When this creature enters, turn any number of target tapped nontoken creatures face down. They're 2/2 Horror creatures.

Illithid Harvester // Plant Tadpoles

Ixidron

As this creature enters, turn all other nontoken creatures face down. (They're 2/2 creatures.)
Ixidron's power and toughness are each equal to the number of face-down creatures on the battlefield.

Cemetery Prowler

Vigilance
Whenever this creature enters or attacks, exile a card from a graveyard.
Spells you cast cost {1} less to cast for each card type they share with cards exiled with this creature.

Port Town

As this land enters, you may reveal a Plains or Island card from your hand. If you don't, this land enters tapped.
{T}: Add {W} or {U}.

Elvish Mystic

Arboreal Grazer

Reach
When this creature enters, you may put a land card from your hand onto the battlefield tapped.

Hidden Dragonslayer

Lifelink
Megamorph {2}{W} (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 this creature is turned face up, destroy target creature with power 4 or greater an opponent controls.

Riptide Entrancer

Whenever this creature deals combat damage to a player, you may sacrifice it. If you do, gain control of target creature that player controls. (This effect lasts indefinitely.)
Morph {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.)

Aven Liberator

Flying
Morph {3}{W} (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 this creature is turned face up, target creature you control gains protection from the color of your choice until end of turn.

Obscuring Aether

Face-down creature spells you cast cost {1} less to cast.
{1}{G}: Turn this enchantment face down. (It becomes a 2/2 creature.)

Willbender

Morph {1}{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 this creature is turned face up, change the target of target spell or ability with a single target.

Sunpetal Grove

This land enters tapped unless you control a Forest or a Plains.
{T}: Add {G} or {W}.

Sage of the Unknowable

{T}: Add {C}. Spend this mana only to cast a colorless spell or to activate an ability.

Fortified Village

As this land enters, you may reveal a Forest or Plains card from your hand. If you don't, this land enters tapped.
{T}: Add {G} or {W}.

Ixidor, Reality Sculptor

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

Deathmist Raptor

Deathtouch
Whenever a permanent you control is turned face up, you may return this card from your graveyard to the battlefield face up or face down.
Megamorph {4}{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.)

Glaring Fleshraker

Whenever you cast a colorless spell, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."
Whenever another colorless creature you control enters, this creature deals 1 damage to each opponent.

Chromeshell Crab

Morph {4}{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 this creature is turned face up, you may exchange control of target creature you control and target creature an opponent controls.

Fyndhorn Elves

Plains

Vengeful Creeper

Disguise {5}{G} (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 this creature is turned face up, destroy target artifact or enchantment an opponent controls.

Inga and Esika

Creatures you control have vigilance and "{T}: Add one mana of any color. Spend this mana only to cast a creature spell."
Whenever you cast a creature spell, if three or more mana from creatures was spent to cast it, draw a card.

Unyielding Gatekeeper

Disguise {1}{W} (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 this creature is turned face up, exile another target nonland permanent. If you controlled it, return it to the battlefield tapped. Otherwise, its controller creates a 2/2 white and blue Detective creature token.

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 this creature is turned face up, counter target instant or sorcery spell.

Three Tree Rootweaver

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 this creature 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.

Mastery of the Unseen

Whenever a permanent you control is turned face up, you gain 1 life for each creature you control.
{3}{W}: Manifest the top card of your 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.)

Icefeather Aven

Flying
Morph {1}{G}{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 this creature is turned face up, you may return another target creature to its owner's hand.

Island

Thousand Winds

Flying
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 this creature is turned face up, return all other tapped creatures to their owners' hands.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Command Tower

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

Monastery Loremaster

Megamorph {5}{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 this creature is turned face up, return target noncreature, nonland card from your graveyard to your hand.

Cloud Key

As this artifact enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Naga Vitalist

{T}: Add one mana of any type that a land you control could produce.

Anthem

Jasmine Boreal of the Seven

{T}: Add {G}{W}. Spend this mana only to cast creature spells with no abilities.
Creatures you control with no abilities can't be blocked by creatures with abilities.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Muraganda Petroglyphs

Avacyn's Pilgrim

Nightshade Dryad

Deathtouch
{T}: Add {C}.
{T}: Add one mana of any color.

Coveted Falcon

Flying
Whenever this creature attacks, gain control of target permanent you own but don't control.
Disguise {1}{U}
When this creature is turned face up, target opponent gains control of any number of target permanents you control. Draw a card for each one they gained control of this way.

Master of Pearls

Morph {3}{W}{W} (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 this creature is turned face up, creatures you control get +2/+2 until end of turn.

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 this creature is turned face up, destroy target artifact or enchantment an opponent controls.

Weathered Bodyguards

As long as this creature is untapped, all combat damage that would be dealt to you by unblocked creatures is dealt to this creature instead.
Morph {3}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Mischievous Quanar

{3}{U}{U}: Turn this creature face down.
Morph {1}{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 this creature is turned face up, copy target instant or sorcery spell. You may choose new targets for that copy.

Vineglimmer Snarl

As this land enters, you may reveal a Forest or Island card from your hand. If you don't, this land enters tapped.
{T}: Add {G} or {U}.

Hinterland Harbor

This land enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

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.

Echo Tracer

Morph {2}{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 this creature is turned face up, return target creature to its owner's hand.

Frontline Strategist

Morph {W} (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 this creature is turned face up, prevent all combat damage non-Soldier creatures would deal this turn.