Xorn

If you would create one or more Treasure tokens, instead create those tokens plus an additional Treasure token.

Juri, Master of the Revue

Whenever you sacrifice a permanent, put a +1/+1 counter on Juri, Master of the Revue.
When Juri dies, it deals damage equal to its power to any target.

Forsworn Paladin

Menace
{1}{B}, {T}, Pay 1 life: Create a Treasure token.
{2}{B}: Target creature gets +2/+0 until end of turn. If mana from a Treasure was spent to activate this ability, that creature also gains deathtouch until end of turn.

Kalain, Reclusive Painter

When Kalain, Reclusive Painter enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Other creatures you control enter with an additional +1/+1 counter on them for each mana from a Treasure spent to cast them.

Blood Aspirant

Whenever you sacrifice a permanent, put a +1/+1 counter on Blood Aspirant.
{1}{R}, {T}, Sacrifice a creature or enchantment: Blood Aspirant deals 1 damage to target creature. That creature can't block this turn.

Slaughter-Priest of Mogis

Whenever you sacrifice a permanent, Slaughter-Priest of Mogis gets +2/+0 until end of turn.
{2}, Sacrifice another creature or an enchantment: Slaughter-Priest of Mogis gains first strike until end of turn.

Volcanic Torrent

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Volcanic Torrent deals X damage to each creature and planeswalker your opponents control, where X is the number of spells you've cast this turn.

Outpost Siege

As Outpost Siege enters, choose Khans or Dragons.
• Khans — At the beginning of your upkeep, exile the top card of your library. Until end of turn, you may play that card.
• Dragons — Whenever a creature you control leaves the battlefield, Outpost Siege deals 1 damage to any target.

Reckless Fireweaver

Whenever an artifact you control enters, Reckless Fireweaver deals 1 damage to each opponent.

Author of Shadows

When Author of Shadows enters, exile all opponents' graveyards. Choose a nonland card exiled this way. You may cast that card for as long as it remains exiled, and you may spend mana as though it were mana of any color to cast that spell.

Mayhem Devil

Whenever a player sacrifices a permanent, Mayhem Devil deals 1 damage to any target.

Havoc Jester

Whenever you sacrifice a permanent, Havoc Jester deals 1 damage to any target.

Dream Devourer

Each nonland card in your hand without foretell has foretell. Its foretell cost is equal to its mana cost reduced by {2}. (During your turn, you may pay {2} and exile it from your hand face down. Cast it on a later turn for its foretell cost.)
Whenever you foretell a card, Dream Devourer gets +2/+0 until end of turn.