You Look Upon the Tarrasque

Choose one —
• Run and Hide — Prevent all combat damage that would be dealt to you and creatures you control this turn.
• Gather Your Courage — Target creature gets +5/+5 and gains indestructible until end of turn. All creatures your opponents control able to block that creature this turn do so.

Questing Beast

Vigilance, deathtouch, haste
Questing Beast can't be blocked by creatures with power 2 or less.
Combat damage that would be dealt by creatures you control can't be prevented.
Whenever Questing Beast deals combat damage to an opponent, it deals that much damage to target planeswalker that player controls.

Snag

You may discard a Forest card rather than pay this spell's mana cost.
Prevent all combat damage that would be dealt by unblocked creatures this turn.

Lull

Prevent all combat damage that would be dealt this turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Roar of Challenge

All creatures able to block target creature this turn do so.
Ferocious — That creature gains indestructible until end of turn if you control a creature with power 4 or greater.

Jaheira's Respite

Search your library for up to X basic land cards, where X is the number of creatures attacking you, put those cards onto the battlefield tapped, then shuffle.
Prevent all combat damage that would be dealt this turn.

Guardian Augmenter

Flash
Commander creatures you control get +2/+2.
Commanders you control have hexproof.

Pause for Reflection

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.)
Prevent all combat damage that would be dealt this turn.

Spore Frog

Sacrifice this creature: Prevent all combat damage that would be dealt this turn.

Predatory Impetus

Enchant creature
Enchanted creature gets +3/+3, must be blocked if able, and is goaded. (It attacks each combat if able and attacks a player other than you if able.)

Chariot of Victory

Equipped creature has first strike, trample, and haste.
Equip {1}

Subdue

Prevent all combat damage that would be dealt by target creature this turn. That creature gets +0/+X until end of turn, where X is its mana value.

Arachnogenesis

Create X 1/2 green Spider creature tokens with reach, where X is the number of creatures attacking you. Prevent all combat damage that would be dealt this turn by non-Spider creatures.

Galadhrim Ambush

Create X 1/1 green Elf Warrior creature tokens, where X is the number of attacking creatures.
Prevent all combat damage that would be dealt this turn by non-Elf creatures.

Bubble Matrix

Prevent all damage that would be dealt to creatures.

Winds of Qal Sisma

Prevent all combat damage that would be dealt this turn.
Ferocious — If you control a creature with power 4 or greater, instead prevent all combat damage that would be dealt this turn by creatures your opponents control.

Thunderfoot Baloth

Trample
Lieutenant — As long as you control your commander, this creature gets +2/+2 and other creatures you control get +2/+2 and have trample.

Prevent all combat damage that would be dealt this turn.

Dawnstrider

{G}, {T}, Discard a card: Prevent all combat damage that would be dealt this turn.

Maze of Ith

{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.

Obscuring Haze

If you control a commander, you may cast this spell without paying its mana cost.
Prevent all damage that would be dealt this turn by creatures your opponents control.

Tangle

Prevent all combat damage that would be dealt this turn.
Each attacking creature doesn't untap during its controller's next untap step.

Blessed Respite

Target player shuffles their graveyard into their library. Prevent all combat damage that would be dealt this turn.

Moment's Peace

Prevent all combat damage that would be dealt this turn.
Flashback {2}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Leery Fogbeast

Whenever this creature becomes blocked, prevent all combat damage that would be dealt this turn.