Swampbenders's second ability causes each land on the battlefield you control to have the land type Swamp in addition to its other types. Any land that's a Swamp has the ability "{T}: Add {B}." Nothing else changes about those lands, including their names, other subtypes, other abilities, and whether they're legendary, basic, or snow.
2025-10-02 • wotc
Land cards not on the battlefield aren't affected by Swampbenders's second ability.
2025-10-02 • wotc