Giggling Skitterspike

Indestructible
Whenever this creature attacks, blocks, or becomes the target of a spell, it deals damage equal to its power to each opponent.
{5}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)

Perimeter Captain

Defender
Whenever a creature you control with defender blocks, you may gain 2 life.

Tangle Asp

Whenever this creature blocks or becomes blocked by a creature, destroy that creature at end of combat.

Favor of the Woods

Enchant creature
Whenever enchanted creature blocks, you gain 3 life.

Spirespine

Bestow {4}{G} (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.)
This creature blocks each combat if able.
Enchanted creature gets +4/+1 and blocks each combat if able.

Elite Javelineer

Whenever this creature blocks, it deals 1 damage to target attacking creature.

Serene Master

Whenever this creature blocks, exchange its power and the power of target creature it's blocking until end of combat.

Aetherplasm

Whenever this creature blocks a creature, you may return this creature to its owner's hand. If you do, you may put a creature card from your hand onto the battlefield blocking that creature.

Pride Guardian

Defender
Whenever this creature blocks, you gain 3 life.

Jedit Ojanen of Efrava

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
Whenever Jedit Ojanen attacks or blocks, create a 2/2 green Cat Warrior creature token with forestwalk.

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}

Meglonoth

Vigilance, trample
Whenever this creature blocks a creature, this creature deals damage to that creature's controller equal to this creature's power.

Nascent Metamorph

Whenever this creature attacks or blocks, target opponent reveals cards from the top of their library until they reveal a creature card. This creature becomes a copy of that card until end of turn. Then that player puts all cards revealed this way on the bottom of their library in a random order.

Smuggler's Copter

Flying
Whenever this Vehicle attacks or blocks, you may draw a card. If you do, discard a card.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Spincrusher

Whenever this creature blocks, put a +1/+1 counter on it.
Remove a +1/+1 counter from this creature: This creature can't be blocked this turn.

Royal Trooper

Whenever this creature blocks, it gets +2/+2 until end of turn.

Freelance Muscle

Whenever this creature attacks or blocks, it gets +X/+X until end of turn, where X is the greatest power and/or toughness among other creatures you control.

Giant Badger

Shape Stealer

Whenever this creature blocks or becomes blocked by a creature, change this creature's base power and toughness to that creature's power and toughness until end of turn.

Elder Gargaroth

Vigilance, reach, trample
Whenever this creature attacks or blocks, choose one —
• Create a 3/3 green Beast creature token.
• You gain 3 life.
• Draw a card.

Tangle Angler

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{G}: Target creature blocks this creature this turn if able.

Shu Defender

Whenever this creature blocks, it gets +0/+2 until end of turn.

Godsend

Equipped creature gets +3/+3.
Whenever equipped creature blocks or becomes blocked by one or more creatures, you may exile one of those creatures.
Your opponents can't cast spells with the same name as a card exiled with Godsend.
Equip {3}

Jareth, Leonine Titan

Whenever Jareth blocks, it gets +7/+7 until end of turn.
{W}: Jareth gains protection from the color of your choice until end of turn.

Wall of Frost

Defender
Whenever this creature blocks a creature, that creature doesn't untap during its controller's next untap step.

Engulfing Slagwurm

Whenever this creature blocks or becomes blocked by a creature, destroy that creature. You gain life equal to that creature's toughness.

Gorgon Recluse

Whenever this creature blocks or becomes blocked by a nonblack creature, destroy that creature at end of combat.
Madness {B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)