The type of value(s) in the container
Counts elements that satisfy the predicate. For single-value containers: returns 0 or 1 For collections: returns the count of matching elements
Tests whether any element satisfies the predicate. For single-value containers: tests the single value For collections: returns true if any element matches
Applies an effect function to each element. For single-value containers: applies to the value if present For collections: applies to each element
Universal operations that work on any container (single-value or collection). These operations make sense for Option, Either, Try, List, Set, etc.