Infernal Medusa

Whenever Infernal Medusa blocks a creature, destroy that creature at end of combat.
Whenever Infernal Medusa becomes blocked by a non-Wall creature, destroy that creature at end of combat.

Luminous Guardian

{W}: Luminous Guardian gets +0/+1 until end of turn.
{2}: Luminous Guardian can block an additional creature this turn.

Engulfing Slagwurm

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

Jukai Trainee

Whenever Jukai Trainee blocks or becomes blocked, it gets +1/+1 until end of turn.

Inferno Elemental

Whenever Inferno Elemental blocks or becomes blocked by a creature, Inferno Elemental deals 3 damage to that creature.

Coastline Chimera

Flying
{1}{W}: Coastline Chimera can block an additional creature this turn.

Trueheart Duelist

Trueheart Duelist can block an additional creature each combat.
Embalm {2}{W} ({2}{W}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Human Warrior with no mana cost. Embalm only as a sorcery.)

Echo Circlet

Equipped creature can block an additional creature each combat.
Equip {1}

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.)

Iona's Blessing

Enchant creature
Enchanted creature gets +2/+2, has vigilance, and can block an additional creature each combat.

Selesnya Sagittars

Reach (This creature can block creatures with flying.)
Selesnya Sagittars can block an additional creature each combat.

Foriysian Interceptor

Flash (You may cast this spell any time you could cast an instant.)
Defender
Foriysian Interceptor can block an additional creature each combat.

Cenn's Tactician

{W}, {T}: Put a +1/+1 counter on target Soldier creature.
Each creature you control with a +1/+1 counter on it can block an additional creature each combat.

Escaped Null

Lifelink
Whenever Escaped Null blocks or becomes blocked, it gets +5/+0 until end of turn.

Deathgazer

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

Mounted Archers

Reach (This creature can block creatures with flying.)
{W}: Mounted Archers can block an additional creature this turn.

Ghastbark Twins

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Ghastbark Twins can block an additional creature each combat.

Foriysian Brigade

Foriysian Brigade can block an additional creature each combat.

Brave the Sands

Creatures you control have vigilance.
Each creature you control can block an additional creature each combat.

Two-Headed Dragon

Flying
Menace (This creature can't be blocked except by two or more creatures.)
Two-Headed Dragon can block an additional creature each combat.
{1}{R}: Two-Headed Dragon gets +2/+0 until end of turn.

Lairwatch Giant

Lairwatch Giant can block an additional creature each combat.
Whenever Lairwatch Giant blocks two or more creatures, it gains first strike until end of turn.

Fibrous Entangler

Vigilance
Fibrous Entangler must be blocked if able.
Fibrous Entangler can block an additional creature each combat.

Tangleclaw Werewolf

Tangleclaw Werewolf can block an additional creature each combat.
{6}{G}: Transform Tangleclaw Werewolf.

Tangleclaw Werewolf // Fibrous Entangler

Spike-Tailed Ceratops

Spike-Tailed Ceratops can block an additional creature each combat.

Watcher in the Web

Reach (This creature can block creatures with flying.)
Watcher in the Web can block an additional seven creatures each combat.

Dread Specter

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

High Ground

Each creature you control can block an additional creature each combat.

Gorgon Recluse

Whenever Gorgon Recluse 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.)

Anurid Swarmsnapper

Reach (This creature can block creatures with flying.)
{1}{G}: Anurid Swarmsnapper can block an additional creature this turn.

Kemba's Legion

Vigilance
Kemba's Legion can block an additional creature each combat for each Equipment attached to Kemba's Legion.

Foriysian Totem

{T}: Add {R}.
{4}{R}: Foriysian Totem becomes a 4/4 red Giant artifact creature with trample until end of turn.
As long as Foriysian Totem is a creature, it can block an additional creature each combat.

Night Market Guard

Night Market Guard can block an additional creature each combat.

Knight of Sorrows

Knight of Sorrows can block an additional creature each combat.
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Act of Heroism

Untap target creature. It gets +2/+2 until end of turn and can block an additional creature this turn.

Hundred-Handed One

Vigilance
{3}{W}{W}{W}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as Hundred-Handed One is monstrous, it has reach and can block an additional ninety-nine creatures each combat.

Entourage of Trest

When Entourage of Trest enters, you become the monarch.
Entourage of Trest can block an additional creature each combat as long as you're the monarch.