Ancient Copper Dragon

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

Sol Ring

Jaws, Relentless Predator

Trample, haste
Whenever Jaws deals combat damage to a player, create that many Blood tokens. (They're artifacts with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")
Whenever a noncreature artifact is sacrificed or destroyed, Jaws deals 1 damage to each opponent.

Marching Duodrone

Whenever this creature attacks, each player creates a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Descent into Avernus

At the beginning of your upkeep, put two descent counters on this enchantment. Then each player creates X Treasure tokens and this enchantment deals X damage to each player, where X is the number of descent counters on this enchantment.

Mountain

Pain Distributor

Menace
Whenever a player casts their first spell each turn, they create a Treasure token.
Whenever an artifact an opponent controls is put into a graveyard from the battlefield, this creature deals 1 damage to that player.