Gideon, Champion of Justice

+1: Put a loyalty counter on Gideon for each creature target opponent controls.
0: Until end of turn, Gideon becomes a Human Soldier creature with power and toughness each equal to the number of loyalty counters on him and gains indestructible. He's still a planeswalker. Prevent all damage that would be dealt to him this turn.
−15: Exile all other permanents.

Have

Aven Redeemer

Flying
{T}: Prevent the next 2 damage that would be dealt to any target this turn.

Condemn

Put target attacking creature on the bottom of its owner's library. Its controller gains life equal to its toughness.

Sunscorch Regent

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on this creature and you gain 1 life.

Wall of Glare

Defender (This creature can't attack.)
This creature can block any number of creatures.

Crib Swap

Changeling (This card is every creature type.)
Exile target creature. Its controller creates a 1/1 colorless Shapeshifter creature token with changeling.

Brave the Sands

Creatures you control have vigilance.
Each creature you control can block an additional creature each combat.

Cast Out

Flash
When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)

Pollen Lullaby

Prevent all combat damage that would be dealt this turn. Clash with an opponent. If you win, creatures that player controls don't untap during the player's next untap step. (Each clashing player reveals the top card of their library, then puts that card on their choice of the top or bottom. A player wins if their card had a greater mana value.)

Mystifying Maze

{T}: Add {C}.
{4}, {T}: Exile target attacking creature an opponent controls. At the beginning of the next end step, return it to the battlefield tapped under its owner's control.

Pursuit of Knowledge

If you would draw a card, you may put a study counter on this enchantment instead.
Remove three study counters from this enchantment, Sacrifice this enchantment: Draw seven cards.

Entangler

Enchant creature
Enchanted creature can block any number of creatures.

Guardian of the Gateless

Flying
This creature can block any number of creatures.
Whenever this creature blocks, it gets +1/+1 until end of turn for each creature it's blocking.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Arcane Encyclopedia

Guardian Idol

This artifact enters tapped.
{T}: Add {C}.
{2}: This artifact becomes a 2/2 Golem artifact creature until end of turn.

Kitsune Palliator

{T}: Prevent the next 1 damage that would be dealt to each creature and each player this turn.

Vengeful Archon

Flying
{X}: Prevent the next X damage that would be dealt to you this turn. If damage is prevented this way, this creature deals that much damage to target player or planeswalker.

Mass Calcify

Palace Guard

This creature can block any number of creatures.

Master Healer

{T}: Prevent the next 4 damage that would be dealt to any target this turn.

Loxodon Anchorite

{T}: Prevent the next 2 damage that would be dealt to any target this turn.

Plains

Storm Herd

Create X 1/1 white Pegasus creature tokens with flying, where X is your life total.

Rune-Tail's Essence

Prevent all damage that would be dealt to creatures you control.

Rune-Tail, Kitsune Ascendant

When you have 30 or more life, flip Rune-Tail.

Rune-Tail, Kitsune Ascendant // Rune-Tail's Essence

Hallowed Healer

{T}: Prevent the next 2 damage that would be dealt to any target this turn.
Threshold — {T}: Prevent the next 4 damage that would be dealt to any target this turn. Activate only if there are seven or more cards in your graveyard.

White Sun's Zenith

Create X 2/2 white Cat creature tokens. Shuffle White Sun's Zenith into its owner's library.

Brave the Elements

Choose a color. White creatures you control gain protection from the chosen color until end of turn.

Parhelion II

Flying, first strike, vigilance
Whenever Parhelion II attacks, create two 4/4 white Angel creature tokens with flying and vigilance that are attacking.
Crew 4 (Tap any number of creatures you control with total power 4 or more: This Vehicle becomes an artifact creature until end of turn.)

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.

Sunset Pyramid

This artifact enters with three brick counters on it.
{2}, {T}, Remove a brick counter from this artifact: Draw a card.
{2}, {T}: Scry 1.

Heliod's Intervention

Choose one —
• Destroy X target artifacts and/or enchantments.
• Target player gains twice X life.

Felidar Sovereign

Vigilance (Attacking doesn't cause this creature to tap.)
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
At the beginning of your upkeep, if you have 40 or more life, you win the game.

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.)

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Story Circle

As this enchantment enters, choose a color.
{W}: The next time a source of your choice of the chosen color would deal damage to you this turn, prevent that damage.

Sanctum Custodian

Selfless Squire

Flash
When this creature enters, prevent all damage that would be dealt to you this turn.
Whenever damage that would be dealt to you is prevented, put that many +1/+1 counters on this creature.

Avacyn, Guardian Angel

Flying, vigilance
{1}{W}: Prevent all damage that would be dealt to another target creature this turn by sources of the color of your choice.
{5}{W}{W}: Prevent all damage that would be dealt to target player or planeswalker this turn by sources of the color of your choice.

Guardian Seraph

Flying
If a source an opponent controls would deal damage to you, prevent 1 of that damage.

Orim's Prayer

Whenever one or more creatures attack you, you gain 1 life for each attacking creature.

Myriad Landscape

This land enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Hundred-Handed One

Vigilance
{3}{W}{W}{W}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as this creature is monstrous, it has reach and can block an additional ninety-nine creatures each combat.

Commander's Sphere

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

Palisade Giant

All damage that would be dealt to you and other permanents you control is dealt to this creature instead.

Oblation

The owner of target nonland permanent shuffles it into their library, then draws two cards.

Riot Control

You gain 1 life for each creature your opponents control. Prevent all damage that would be dealt to you this turn.

Ironfist Crusher

This creature can block any number of creatures.
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.)

Prismatic Lens

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

Channel Harm

Prevent all damage that would be dealt to you and permanents you control this turn by sources you don't control. If damage is prevented this way, you may have Channel Harm deal that much damage to target creature.

Invulnerability

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
The next time a source of your choice would deal damage to you this turn, prevent that damage.

Ravnica at War

Return to Dust

Exile target artifact or enchantment. If you cast this spell during your main phase, you may exile up to one other target artifact or enchantment.

Approach of the Second Sun

If this spell was cast from your hand and you've cast another spell named Approach of the Second Sun this game, you win the game. Otherwise, put Approach of the Second Sun into its owner's library seventh from the top and you gain 7 life.

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Burnished Hart

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

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Pariah

Enchant creature
All damage that would be dealt to you is dealt to enchanted creature instead.

Sol Ring

Righteous Cause

Whenever a creature attacks, you gain 1 life.

Dawn Charm

Choose one —
• Prevent all combat damage that would be dealt this turn.
• Regenerate target creature.
• Counter target spell that targets you.

Aegis Angel

Flying (This creature can't be blocked except by creatures with flying or reach.)
When this creature enters, another target permanent gains indestructible for as long as you control this creature. (Effects that say "destroy" don't destroy it. A creature with indestructible can't be destroyed by damage.)

Gideon Blackblade

During your turn, Gideon Blackblade is a 4/4 Human Soldier creature with indestructible that's still a planeswalker.
Prevent all damage that would be dealt to Gideon Blackblade during your turn.
+1: Up to one other target creature you control gains your choice of vigilance, lifelink, or indestructible until end of turn.
−6: Exile target nonland permanent.

Gideon, the Oathsworn

Whenever you attack with two or more non-Gideon creatures, put a +1/+1 counter on each of those creatures.
+2: Until end of turn, Gideon becomes a 5/5 white Soldier creature that's still a planeswalker. Prevent all damage that would be dealt to him this turn. (He can't attack if he was cast this turn.)
−9: Exile Gideon and each creature your opponents control.

Ghosts of the Innocent

If a source would deal damage to a permanent or player, it deals half that damage, rounded down, to that permanent or player instead.

Illuminated Folio

{1}, {T}, Reveal two cards from your hand that share a color: Draw a card.

Bonder's Ornament

{T}: Add one mana of any color.
{4}, {T}: Each player who controls a permanent named Bonder's Ornament draws a card.