Mollusks:
* Snails: Land snails, sea snails, and slugs.
* Clams: Includes clams, oysters, mussels, and scallops.
* Squid and Octopus: Though they have an internal shell (called a pen or gladius) that is not visible from the outside.
Arthropods:
* Crabs: All types of crabs.
* Lobsters: Including lobsters, crawfish, and shrimp.
* Turtles: Both sea turtles and land turtles.
* Tortoises: Land turtles with dome-shaped shells.
Other:
* Chitons: Marine mollusks with 8 overlapping plates that form a shell.
* Brachiopods: Marine animals with two hinged shells.
* Sea Urchins: Have a hard, spiny shell.
* Sea Stars (Starfish): Have a tough, calcified skin, not a true shell.
This is not an exhaustive list, but it covers the most common animals with shells.