Sonic Robo Blast 2

The Crushstacean appears in the Deep Sea Zone in both acts.

Another Crab's Treasure (Demo)

WarioWare: Smooth Moves

This Wario crab has a chance to appear during any level of the Climate Control microgame.

WarioWare: Smooth Moves

This crab can appears in the Shoot the Breeze microgame, during it's first level.

Bomb Rush Cyberfunk

This crab appears as the large graffiti for the Devil Theory gang, and can be obtained after completing the main story.

E.V.O.: Search for Eden

These appear in the game's second chapter, Early Creatures of Land, as food.

Silent Hill

This crab appears in a puzzle relating to star signs, and is representative of the constellation Cancer.

Image submitted by @stoic--rose.

Jumping Flash!

Crabs can be found in the first level of the game's fourth world, Wonderland on Ice.

Hotline Miami 2: Wrong Number

Image submitted by @catgirlscratches.

Lobsters in Games: Kingdom Hearts III

In the field, the lobster model is used for the lobster ingredient, but also for crabs. The only unique model for crabs is used instead for white crabs. Both a crab and a lobster can be found in the general seafood menu icon.

Crabs as an ingredient can be found underwater in The Caribbean, with lobsters also available in the Kingdom of Corona.

Lobsters in Games: Xenoblade Chronicles 3

The Crustip line of enemies first appeared in Xenoblade Chronicles 2.

Lobsters in Games: Persona 5 Royal

Lobsters in Games: Picross 3D: Round 2

Lobsters in Games: Yume 2kki

There are two lobsters that use this sprite; one is the passive Okina Robusuta, who appears in the underwater section of the Flooded Baths world. The other is the hostile Killer Lobster, which is rather unique, as it cannot be encountered normally. It only appears while the player has Noclip Mode active in the Highway and Neon Highway worlds. It is also the most dangerous chaser in the entire game, as upon contact, the player is sent directly to the title screen rather than to an isolated location or even simply waking up.

Stardew Valley

Yume 2kki

This crab appears in Fish Oil World. It can warp you between the main area and the Crab Swamp.

Stardew Valley

Rock crabs appear in the first 30 levels of the mines, with a variation appearing in the depths.

Rock crabs have a small chance of dropping a crab.