Canyon Crab

{1}{U}: Canyon Crab gets +2/-2 until end of turn.
At the beginning of your end step, if you haven't cast a spell from your hand this turn, draw a card, then discard a card.

King Crab

{1}{U}, {T}: Put target green creature on top of its owner's library.

Riptide Crab

Vigilance
When Riptide Crab dies, draw a card.

Chromeshell Crab

Morph {4}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Chromeshell Crab is turned face up, you may exchange control of target creature you control and target creature an opponent controls.

Giant Octopus

Ancient Crab

Mirrorshell Crab

Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Channel — {2}{U}, Discard Mirrorshell Crab: Counter target spell or ability unless its controller pays {3}.

Sharktocrab

{2}{G}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Sharktocrab, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Fortress Crab

Purple-Crystal Crab

When Purple-Crystal Crab dies, draw a card.

Horseshoe Crab

Scrabbling Claws

{T}: Target player exiles a card from their graveyard.
{1}, Sacrifice Scrabbling Claws: Exile target card from a graveyard. Draw a card.

Wishcoin Crab

Giant Crab

{U}: Giant Crab gains shroud until end of turn. (It can't be the target of spells or abilities.)

Octopus

Ruin Crab

Landfall — Whenever a land you control enters, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

Crab Umbra

Enchant creature
{2}{U}: Untap enchanted creature.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Wormfang Crab

Wormfang Crab can't be blocked.
When Wormfang Crab enters, an opponent chooses a permanent you control other than Wormfang Crab and exiles it.
When Wormfang Crab leaves the battlefield, return the exiled card to the battlefield under its owner's control.