Existential.Net (nuget): The library for things that may or may not exist.  Existential is a utility library that contains parameter validation methods, a Maybe monad, and more. It can be used to work effectively with nulls, to efficiently resolve Code Analysis issues CA1062 and CA2000, to help generate a hash code, and to convert the names of generic types into a familiar string representation.
Keywords: validation|validate|optional|types|maybe|Optional<T>|Maybe<T>|null|nulls|generic|names|reflection|exception|filter|logging|when