Amulet of Safekeeping

Whenever you become the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.
Creature tokens get -1/-0.

Gary Clone

Squad {2} (As an additional cost to cast this spell, you may pay {2} any number of times. When this creature enters, create that many tokens that are copies of it.)
Whenever Gary Clone attacks, each creature you control named Gary Clone gets +1/+0 until end of turn.

Apothecary White

Vigilance
Whenever you attack, you create a Food token for each player being attacked. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{W}, {T}, Tap X untapped Foods you control: Create X 1/1 white Human creature tokens.

Overencumbered

Enchant opponent
When Overencumbered enters, enchanted opponent creates a Clue token, a Food token, and a Junk token.
At the beginning of combat on enchanted opponent's turn, that player may pay {1} for each artifact they control. If they don't, creatures can't attack this combat.

Feral Ghoul

Menace
Whenever another creature you control dies, put a +1/+1 counter on Feral Ghoul.
When Feral Ghoul dies, each opponent gets a number of rad counters equal to its power.

Caesar, Legion's Emperor

Whenever you attack, you may sacrifice another creature. When you do, choose two —
• Create two 1/1 red and white Soldier creature tokens with haste that are tapped and attacking.
• You draw a card and you lose 1 life.
• Caesar, Legion's Emperor deals damage equal to the number of creature tokens you control to target opponent.

Akroan Horse

Defender
When Akroan Horse enters, an opponent gains control of it.
At the beginning of your upkeep, each opponent creates a 1/1 white Soldier creature token.

Abhorrent Overlord

Flying
When Abhorrent Overlord enters, create a number of 1/1 black Harpy creature tokens with flying equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
At the beginning of your upkeep, sacrifice a creature.

Ancient Copper Dragon

Flying
Whenever Ancient Copper Dragon deals combat damage to a player, roll a d20. You create a number of Treasure tokens equal to the result.

Ancestral Blade

When Ancestral Blade enters, create a 1/1 white Soldier creature token, then attach Ancestral Blade to it.
Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Afterlife Insurance

Creatures you control gain afterlife 1 until end of turn. Draw a card. (When a creature with afterlife 1 dies, create a 1/1 white and black Spirit creature token with flying.)

Anim Pakal, Thousandth Moon

Whenever you attack with one or more non-Gnome creatures, put a +1/+1 counter on Anim Pakal, then create X 1/1 colorless Gnome artifact creature tokens that are tapped and attacking, where X is the number of +1/+1 counters on Anim Pakal.

Adipose Offspring

Emerge {5}{W} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When Adipose Offspring enters, create a 2/2 white Alien creature token. If Adipose Offspring's emerge cost was paid, instead create X of those tokens, where X is the sacrificed creature's toughness.

Alliance of Arms

Join forces — Starting with you, each player may pay any amount of mana. Each player creates X 1/1 white Soldier creature tokens, where X is the total amount of mana paid this way.

Anointed Procession

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

V.A.T.S.

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Choose any number of target creatures with equal toughness. Destroy the chosen creatures.

Idolized

Enchant creature
Enchanted creature has "Whenever this creature attacks alone, it gets +X/+X until end of turn, where X is the number of nonland permanents you control."

Ancient Gold Dragon

Flying
Whenever Ancient Gold Dragon deals combat damage to a player, roll a d20. You create a number of 1/1 blue Faerie Dragon creature tokens with flying equal to the result.

Command Tower

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

Angrath, Captain of Chaos

Creatures you control have menace.
−2: Amass Zombies 2. (Put two +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Anointer Priest

Whenever a creature token you control enters, you gain 1 life.
Embalm {3}{W} ({3}{W}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Human Cleric with no mana cost. Embalm only as a sorcery.)