Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on this artifact. Then if it has eight or more night counters on it, remove all of them and create eight colorless snow artifact tokens named Replicated Ring with "{T}: Add one mana of any color."

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 this creature enters, create a 2/2 white Alien creature token. If this creature's emerge cost was paid, instead create X of those tokens, where X is the sacrificed creature's toughness.

Reef Worm

When this creature dies, create a 3/3 blue Fish creature token with "When this token dies, create a 6/6 blue Whale creature token with 'When this token dies, create a 9/9 blue Kraken creature token.'"

Marneus Calgar

Double strike
Master Tactician — Whenever one or more tokens you control enter, draw a card.
Chapter Master — {6}: Create two 2/2 white Astartes Warrior creature tokens with vigilance.

Minn, Wily Illusionist

Whenever you draw your second card each turn, create a 1/1 blue Illusion creature token with "This token gets +1/+0 for each other Illusion you control."
Whenever an Illusion you control dies, you may put a permanent card with mana value less than or equal to that creature's power from your hand onto the battlefield.

Bitterblossom

At the beginning of your upkeep, you lose 1 life and create a 1/1 black Faerie Rogue creature token with flying.

Wall of Kelp

Defender (This creature can't attack.)
{U}{U}, {T}: Create a 0/1 blue Plant Wall creature token with defender named Kelp.

Geist of Saint Traft

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever Geist of Saint Traft attacks, create a 4/4 white Angel creature token with flying that's tapped and attacking. Exile that token at end of combat.

Ratonhnhaké꞉ton

As long as Ratonhnhaké꞉ton hasn't dealt damage yet, it has hexproof and can't be blocked.
Whenever Ratonhnhaké꞉ton deals combat damage to a player, create a 1/1 black Assassin creature token with menace. When you do, return target Equipment card from your graveyard to the battlefield, then attach it to that token.

Urza's Factory

{T}: Add {C}.
{7}, {T}: Create a 2/2 colorless Assembly-Worker artifact creature token.