Nonbasic land

Nonbasic lands are lands that do not have the basic supertype.

As per Magic rules, only 4 of each nonbasic land can be in a deck at any one time. Basic lands do not have this restriction. Nonbasic lands often depict notable locations from the relevant set's style guide.

Note that a nonbasic land may have a basic land type (Plains, Island, etc).

Rules

From the glossary of the Comprehensive Rules (June 7, 2024—Modern Horizons 3)

Nonbasic Land

Any land that doesn’t have the supertype “basic.” See rule 205.4, “Supertypes.”

Nonbasic land types

Nonbasic land types are essentially all land types which do not appear on a basic land.