Shield of the Avatar

If a source would deal damage to equipped creature, prevent X of that damage, where X is the number of creatures you control.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Shield of the Righteous

Equipped creature gets +0/+2 and has vigilance.
Whenever equipped creature blocks a creature, that creature doesn't untap during its controller's next untap step.
Equip {2}

Haazda Shield Mate

At the beginning of your upkeep, sacrifice Haazda Shield Mate unless you pay {W}{W}.
{W}: The next time a source of your choice would deal damage to you this turn, prevent that damage.

Shield's Might

Target creature gets +2/+2 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Garenbrig Carver

Garenbrig Carver // Shield's Might

Stalwart Shield-Bearers

Defender
Other creatures you control with defender get +0/+2.

Screaming Shield

Equipped creature gets +0/+3 and has "{2}, {T}: Target player mills three cards."
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Elgaud Shieldmate

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Elgaud Shieldmate is paired with another creature, both creatures have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Mourner's Shield

Imprint — When Mourner's Shield enters, you may exile target card from a graveyard.
{2}, {T}: Prevent all damage that would be dealt this turn by a source of your choice that shares a color with the exiled card.

Order of the White Shield

Protection from black
{W}: Order of the White Shield gains first strike until end of turn.
{W}{W}: Order of the White Shield gets +1/+0 until end of turn.

Guardian Shield-Bearer

Megamorph {3}{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 Guardian Shield-Bearer is turned face up, put a +1/+1 counter on another target creature you control.

Estwald Shieldbasher

Whenever Estwald Shieldbasher attacks, you may pay {1}. If you do, it gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Shield of Duty and Reason

Enchant creature
Enchanted creature has protection from green and from blue.

Drogskol Shieldmate

Flash (You may cast this spell any time you could cast an instant.)
When Drogskol Shieldmate enters, other creatures you control get +0/+1 until end of turn.

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.)

Wall of Shields

Defender (This creature can't attack.)
Banding (If any creatures with banding you control are blocking a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by.)

Vernadi Shieldmate

Staunch Shieldmate

Accorder's Shield

Equipped creature gets +0/+3 and has vigilance. (Attacking doesn't cause it to tap.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Shield Mate

Sacrifice Shield Mate: Target creature gets +0/+4 until end of turn.

Linvala, Shield of Sea Gate

Flying
At the beginning of combat on your turn, if you have a full party, choose target nonland permanent an opponent controls. Until your next turn, it can't attack or block, and its activated abilities can't be activated.
Sacrifice Linvala: Choose hexproof or indestructible. Creatures you control gain that ability until end of turn.

Cathar's Shield

Equipped creature gets +0/+3 and has vigilance.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Shield of Kaldra

Equipment named Sword of Kaldra, Shield of Kaldra, and Helm of Kaldra have indestructible.
Equipped creature has indestructible. (Damage and effects that say "destroy" don't destroy it.)
Equip {4}

Pariah's Shield

All damage that would be dealt to you is dealt to equipped creature instead.
Equip {3}

Kite Shield

Equipped creature gets +0/+3.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

White Shield Crusader

Protection from black
{W}: White Shield Crusader gains flying until end of turn.
{W}{W}: White Shield Crusader gets +1/+0 until end of turn.

Shield Bearer

Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Shield of the Realm

If a source would deal damage to equipped creature, prevent 2 of that damage.
Equip {1}

Valkmira, Protector's Shield

If a source an opponent controls would deal damage to you or a permanent you control, prevent 1 of that damage.
Whenever you or another permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.

Reidane, God of the Worthy

Flying, vigilance
Snow lands your opponents control enter tapped.
Noncreature spells your opponents cast with mana value 4 or greater cost {2} more to cast.

Reidane, God of the Worthy // Valkmira, Protector's Shield

Shield Wall

Creatures you control get +0/+2 until end of turn.

Paladin's Shield

Flash
When Paladin's Shield enters, attach it to target creature you control.
Equipped creature gets +0/+2.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Join Shields

Untap all creatures you control. They gain hexproof and indestructible until end of turn. (They can't be the targets of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy them.)

Delaying Shield

If damage would be dealt to you, put that many delay counters on Delaying Shield instead.
At the beginning of your upkeep, remove all delay counters from Delaying Shield. For each delay counter removed this way, you lose 1 life unless you pay {1}{W}.

Mirror Shield

Equipped creature gets +0/+2 and has hexproof and "Whenever a creature with deathtouch blocks or becomes blocked by this creature, destroy that creature."
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Shields of Velis Vel

Changeling (This card is every creature type.)
Creatures target player controls get +0/+1 and gain all creature types until end of turn.

Burrenton Shield-Bearers

Whenever Burrenton Shield-Bearers attacks, target creature gets +0/+3 until end of turn.

Burning Shield Askari

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
{R}{R}: Burning Shield Askari gains first strike until end of turn.

Makindi Shieldmate

Defender
Whenever Makindi Shieldmate or another Ally you control enters, you may put a +1/+1 counter on Makindi Shieldmate.

Ephemeral Shields

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Target creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Shield Dancer

{2}{W}: The next time target attacking creature would deal combat damage to Shield Dancer this turn, that creature deals that damage to itself instead.

Rimeshield Frost Giant

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)

Kry Shield

{2}, {T}: Prevent all damage that would be dealt this turn by target creature you control. That creature gets +0/+X until end of turn, where X is its mana value.

Faith's Shield

Target permanent you control gains protection from the color of your choice until end of turn.
Fateful hour — If you have 5 or less life, instead you and each permanent you control gain protection from the color of your choice until end of turn.

Briar Shield

Enchant creature
Enchanted creature gets +1/+1.
Sacrifice Briar Shield: Enchanted creature gets +3/+3 until end of turn.

Nyxborn Shieldmate

Bestow {2}{W} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Enchanted creature gets +1/+2.

Kithkin Shielddare

{W}, {T}: Target blocking creature gets +2/+2 until end of turn.

Beskir Shieldmate

When Beskir Shieldmate dies, create a 1/1 white Human Warrior creature token.

Vanguard's Shield

Equipped creature gets +0/+3 and can block an additional creature each combat.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)