Simple Guard developed for .NET Standard.
The package is available via NuGet
Check.NotNull(myString, nameof(myString));
Check.NotEmpty(myString, nameof(myString));
Check.NotEmpty(myList, nameof(myList));
Check.NotEmpty(myGuid, nameof(myGuid));
Check.NotWhitespace(myString, nameof(myString));
Check.NotNullOrEmpty(myString, nameof(myString));
Check.NotNullOrWhitespace(myString, nameof(myString));
Check.InRange(myInt > 0, nameof(myInt), myInt);
Check.If(myInt == 3, () => new ArgumentException());