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.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Dawnfeather Eagle

Flying
When Dawnfeather Eagle enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Mind Stone

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

Leonin Lightscribe

Magecraft — Whenever you cast or copy an instant or sorcery spell, creatures you control get +1/+1 until end of turn.

Goring Ceratops

Double strike
Whenever Goring Ceratops attacks, other creatures you control gain double strike until end of turn.

Canyon Jerboa

Landfall — Whenever a land you control enters, creatures you control get +1/+1 until end of turn.

Ajani, Wise Counselor

+2: You gain 1 life for each creature you control.
−3: Creatures you control get +2/+2 until end of turn.
−9: Put X +1/+1 counters on target creature, where X is your life total.

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Leonin Abunas

Artifacts you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Resplendent Mentor

White creatures you control have "{T}: You gain 1 life."

Break of Day

Creatures you control get +1/+1 until end of turn.
Fateful hour — If you have 5 or less life, those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Sanctified Charge

Creatures you control get +2/+1 until end of turn. White creatures you control also gain first strike until end of turn. (They deal combat damage before creatures without first strike.)

Bond of Discipline

Tap all creatures your opponents control. Creatures you control gain lifelink until end of turn.

Benalish Marshal

Make a Stand

Creatures you control get +1/+0 and gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

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}

Kytheon's Tactics

Creatures you control get +2/+1 until end of turn.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, those creatures also gain vigilance until end of turn. (Attacking doesn't cause them to tap.)

Thunderhawk Gunship

Flying
When Thunderhawk Gunship enters, create two 2/2 white Astartes Warrior creature tokens with vigilance.
Whenever Thunderhawk Gunship attacks, attacking creatures you control gain flying until end of turn.
Crew 2

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Battershield Warrior

Boast — {1}{W}: Creatures you control get +1/+1 until end of turn. (Activate only if this creature attacked this turn and only once each turn.)

Arcane Signet

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

Angel of the Dawn

Flying
When Angel of the Dawn enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Mirage Mirror

{2}: Mirage Mirror becomes a copy of target artifact, creature, enchantment, or land until end of turn.

Tenacity

Creatures you control get +1/+1 and gain lifelink until end of turn. Untap those creatures. (Damage dealt by those creatures also causes you to gain that much life.)

Paragon of New Dawns

Other white creatures you control get +1/+1.
{W}, {T}: Another target white creature you control gains vigilance until end of turn. (Attacking doesn't cause it to tap.)

Marshaling Cry

Creatures you control get +1/+1 and gain vigilance until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)
Flashback {3}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Soul of Theros

Vigilance
{4}{W}{W}: Creatures you control get +2/+2 and gain first strike and lifelink until end of turn.
{4}{W}{W}, Exile Soul of Theros from your graveyard: Creatures you control get +2/+2 and gain first strike and lifelink until end of turn.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Angelic Guardian

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever one or more creatures you control attack, they gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Anointer of Valor

Flying
Whenever a creature attacks, you may pay {3}. When you do, put a +1/+1 counter on that creature.

Plains

Commander's Sphere

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

For the Emperor!

Creatures you control get +2/+2 and gain vigilance and lifelink until end of turn.

Captain of the Watch

Vigilance (Attacking doesn't cause this creature to tap.)
Other Soldier creatures you control get +1/+1 and have vigilance.
When Captain of the Watch enters, create three 1/1 white Soldier creature tokens.

Thought Vessel

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

Silverflame Ritual

Put a +1/+1 counter on each creature you control.
Adamant — If at least three white mana was spent to cast this spell, creatures you control gain vigilance until end of turn.

Rush of Battle

Creatures you control get +2/+1 until end of turn. Warrior creatures you control gain lifelink until end of turn. (Damage dealt by those Warriors also causes their controller to gain that much life.)

Aetherstorm Roc

Flying
Whenever Aetherstorm Roc or another creature you control enters, you get {E} (an energy counter).
Whenever Aetherstorm Roc attacks, you may pay {E}{E}. If you do, put a +1/+1 counter on it and tap up to one target creature defending player controls.

Adaptive Automaton

As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
Other creatures you control of the chosen type get +1/+1.

Gilded Lotus

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

Fellwar Stone

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

Myrel, Shield of Argive

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.
Whenever Myrel, Shield of Argive attacks, create X 1/1 colorless Soldier artifact creature tokens, where X is the number of Soldiers you control.

Ambush Paratrooper

Flash
Flying
{5}: Creatures you control get +1/+1 until end of turn.

Sol Ring

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Ancestor Dragon

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

Mondrak, Glory Dominus

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
{1}{W/P}{W/P}, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak, Glory Dominus. ({W/P} can be paid with either {W} or 2 life.)

Plated Onslaught

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Creatures you control get +2/+1 until end of turn.

Stalwart Pathlighter

Vigilance
Coven — At the beginning of combat on your turn, if you control three or more creatures with different powers, creatures you control gain indestructible until end of turn.

Felidar Retreat

Landfall — Whenever a land you control enters, choose one —
• Create a 2/2 white Cat Beast creature token.
• Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.

Akroma's Memorial

Creatures you control have flying, first strike, vigilance, trample, haste, and protection from black and from red.

Steadfast Unicorn

{3}{W}: Creatures you control get +1/+1 and gain vigilance until end of turn. Activate only during your turn. (Attacking doesn't cause them to tap.)

Ao, the Dawn Sky

Flying, vigilance
When Ao, the Dawn Sky dies, choose one —
• Look at the top seven cards of your library. Put any number of nonland permanent cards with total mana value 4 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
• Put two +1/+1 counters on each permanent you control that's a creature or Vehicle.