Top 20 NuGet some Packages

Optional is a robust option/maybe type for C#.
Various useful functionality for Optional.
Useful Optional extensions for working with collections.
A set of assertions for FluentAssertions which provides strong-typed assertions for instances of Optional.
A robust option type for C#.
An Option type for C# (retargeted for netstandard). Forked from See for documentation.
Binaries for the Option type. Visit for an overview and usage examples.
Guard your methods' Ins and Outs. Helpers to add semantics to the optionality of your parameters and results from method calls.
Extension methods and other objects for integrating the Optional# Optional type into .NET.
Provides support polymorphic types in C#, such as Covariant and Invariant Maybe (Optional) types, and type unions.
Yet another implementation of an option/optional type for .NET. An Optional type explicitly represents the type of a value that may or may not exist. While you can do this with nulls, that has many drawbacks. Some of the benefits of this library over some others include comprehensive equality supp...
A simple and easy to use option type for C#.
Optional is a robust option/maybe type for C#.
Provides a type to represent the lack of a value. The behaviour is comparable to using nullable reference types with forced null checks before dereferencing. The package also provides a set of extension methods to enable a fluent functional pattern using Map and Filter.
A .NET Standard library that adds option semantics to a tuple of Boolean and T.
Library that supports functional programming patterns in C#.
Implementation of the Option pattern (also called Maybe pattern) for the .NET platform. For documentation and examples of use, see project website.
A package containing an Option<T> class that functions like a Haskell Maybe type. It is meant to replace certain instances where null is normally used.
DI Friendly implementation of the options pattern