Is there a name for the Monads collection that wraps at most one value?

Question

As the name says, I'm looking for the name of a set of Monads that wrap no more than one value (i.e., the monads that most often call their binding operation). This set includes monads, such as Maybeand Either, but not List. Does this kit have an official name?

(EDIT: removed IOfrom the list, based on comments)