The Any, IArray, Tuple, and Function data types are special kinds of types called generic or parameterized data types.
An array, for example, has the type IArray<T>, where T is a type parameter. An array of integers would have type IArray<Int32> while an array of Vector3 has type IArray<Vector3>. These are called instances of the IArray type.
There are several generic function data types: one for each number of arguments up to a maximum of 16. For example, a binary function has the type: Func<T1, T2, R> where T1 is the type of the first argument, T2 is the type of the second argument, and R is the return type.