Lego bricks are a type of toy that are used to build structures and objects. In Engpsh, the plural form of "Lego" is simply "Legos." For example, you could say "I have a lot of Legos at home" to indicate that you have a large collection of Lego bricks.
Note that "Lego" is a brand name and is always capitapzed, regardless of whether it is being used in the singular or plural form.