Top 20 NuGet reactive Packages

Redux implementation for C# with reactive extensions support
Functional-Reactive for .NET and WPF/XAML
Reactive Extension
Spreads.Utils
Helps to write expressions like: myViewModel.Track(vm => vm.A.B.C.Name) and be sure to get notified whenewer vm.A, or A.B, or C.Name changed.
P# is a framework for building reliable asynchronous software.
Reactive model package to help develop MVVM / reactive oriented models.
Active List Extensions provides a set of linq extensions that dynamically update and throw collection change notifications.