Rabid Elephant

Whenever Rabid Elephant becomes blocked, it gets +2/+2 until end of turn for each creature blocking it.

Sword of Forge and Frontier

Equipped creature gets +2/+2 and has protection from red and from green.
Whenever equipped creature deals combat damage to a player, exile the top two cards of your library. You may play those cards this turn. You may play an additional land this turn.
Equip {2}

Old Gnawbone

Flying
Whenever a creature you control deals combat damage to a player, create that many Treasure tokens.

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Taunting Elf

All creatures able to block Taunting Elf do so.

Gisela, the Broken Blade

Flying, first strike, lifelink
At the beginning of your end step, if you both own and control Gisela, the Broken Blade and a creature named Bruna, the Fading Light, exile them, then meld them into Brisela, Voice of Nightmares.

Sylvan Basilisk

Whenever Sylvan Basilisk becomes blocked by a creature, destroy that creature.

Duskworker

Whenever Duskworker becomes blocked, regenerate it.
{3}: Duskworker gets +1/+0 until end of turn.

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you control.

Gustcloak Runner

Whenever Gustcloak Runner becomes blocked, you may untap it and remove it from combat.

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Revenge of the Hunted

Until end of turn, target creature gets +6/+6 and gains trample, and all creatures able to block it this turn do so.
Miracle {G} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Rust Scarab

Whenever Rust Scarab becomes blocked, you may destroy target artifact or enchantment defending player controls.

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Windswept Heath

{T}, Pay 1 life, Sacrifice Windswept Heath: Search your library for a Forest or Plains card, put it onto the battlefield, then shuffle.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Bountiful Promenade

Bountiful Promenade enters the battlefield tapped unless you have two or more opponents.
{T}: Add {G} or {W}.

Prized Unicorn

All creatures able to block Prized Unicorn do so.

Temple Garden

({T}: Add {G} or {W}.)
As Temple Garden enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Drelnoch

Whenever Drelnoch becomes blocked, you may draw two cards.

Ragnar

{G}{W}{U}, {T}: Regenerate target creature.

Chambered Nautilus

Whenever Chambered Nautilus becomes blocked, you may draw a card.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Bruna, the Fading Light

When you cast this spell, you may return target Angel or Human creature card from your graveyard to the battlefield.
Flying, vigilance
(Melds with Gisela, the Broken Blade.)

Owlbear Cub

Mama's Coming — Whenever Owlbear Cub attacks a player who controls eight or more lands, look at the top eight cards of your library. You may put a creature card from among them onto the battlefield tapped and attacking that player. Put the rest on the bottom of your library in a random order.

Glacial Fortress

Glacial Fortress enters the battlefield tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Tolarian Entrancer

Whenever Tolarian Entrancer becomes blocked by a creature, gain control of that creature at end of combat.

Pygmy Troll

Whenever Pygmy Troll becomes blocked by a creature, Pygmy Troll gets +1/+1 until end of turn.
{G}: Regenerate Pygmy Troll.

Elven Warhounds

Whenever Elven Warhounds becomes blocked by a creature, put that creature on top of its owner's library.

Eiganjo, Seat of the Empire

{T}: Add {W}.
Channel — {2}{W}, Discard Eiganjo, Seat of the Empire: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Port Inspector

Whenever Port Inspector becomes blocked, you may look at defending player's hand.

Nemesis Mask

All creatures able to block equipped creature do so.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery. This card enters the battlefield unattached and stays on the battlefield if the creature leaves.)

Eldrazi Conscription

Enchant creature
Enchanted creature gets +10/+10 and has trample and annihilator 2. (Whenever it attacks, defending player sacrifices two permanents.)

Copperhorn Scout

Whenever Copperhorn Scout attacks, untap each other creature you control.

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Birds of Paradise

Elvish Bard

All creatures able to block Elvish Bard do so.

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

Magewright's Stone

{1}, {T}: Untap target creature that has an activated ability with {T} in its cost.

Spara's Headquarters

({T}: Add {G}, {W}, or {U}.)
Spara's Headquarters enters the battlefield tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Ledger Shredder

Flying
Whenever a player casts their second spell each turn, Ledger Shredder connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Sol Ring

Gang of Elk

Whenever Gang of Elk becomes blocked, it gets +2/+2 until end of turn for each creature blocking it.

Lure

Enchant creature
All creatures able to block enchanted creature do so.

Grasping Giant

Vigilance
Whenever Grasping Giant becomes blocked by a creature, exile that creature until Grasping Giant leaves the battlefield.

Bruna, Light of Alabaster

Flying, vigilance
Whenever Bruna, Light of Alabaster attacks or blocks, you may attach to it any number of Auras on the battlefield and you may put onto the battlefield attached to it any number of Aura cards that could enchant it from your graveyard and/or hand.

Breeding Pool

({T}: Add {G} or {U}.)
As Breeding Pool enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Arcane Signet

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

Bear Umbra

Enchant creature
Enchanted creature gets +2/+2 and has "Whenever this creature attacks, untap all lands you control."
Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Zilortha, Apex of Ikoria

Reach
For each non-Human creature you control, you may have that creature assign its combat damage as though it weren't blocked.

Invasion of Ikoria

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Ikoria enters the battlefield, search your library and/or graveyard for a non-Human creature card with mana value X or less and put it onto the battlefield. If you search your library this way, shuffle.

Invasion of Ikoria // Zilortha, Apex of Ikoria

Golgari Decoy

All creatures able to block Golgari Decoy do so.
Scavenge {3}{G}{G} ({3}{G}{G}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Sword of Feast and Famine

Equipped creature gets +2/+2 and has protection from black and from green.
Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control.
Equip {2}

Indrik Umbra

Enchant creature
Enchanted creature gets +4/+4 and has first strike, and all creatures able to block it do so.
Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Nessian Boar

All creatures able to block Nessian Boar do so.
Whenever Nessian Boar becomes blocked by a creature, that creature's controller draws a card.

Sparring Golem

Whenever Sparring Golem becomes blocked, it gets +1/+1 until end of turn for each creature blocking it.

Basalt Golem

Basalt Golem can't be blocked by artifact creatures.
Whenever Basalt Golem becomes blocked by a creature, that creature's controller sacrifices it at end of combat. If the player does, they create a 0/2 colorless Wall artifact creature token with defender.