Top 20 NuGet settings Packages

CaveSystems INI File Library. This packages contains classes for ini(tialization file) based configurations.
Recommended Google client library to access the Google Cloud Security Command Center Settings API.
Shiny BluetoothLE Hosting - Advertising and GATT server functionality
BizTalk.Factory's environment settings definition DSL for general purpose BizTalk Server application binding definition parameterization.
Cross-platform routines needed in most desktop applications and not only them: - settings manager that supersedes .NET ConfigurationManager; - logger with multi-threading and session support; - auxiliary routines;
SimpleSettings allow applications to use configurations values from any data store in the type of interfaces, thus decouples the frameworks from your appliaction and allowing application to inject interfaces and nothing else. This framework should be used instead of .Net Core IOptions<T>.
Support for combination of settings from multiple sources for Serilog
Flexberry UserSettingsService package.
SimpleConfig allow applications to use configurations values from any data store in the type of interfaces, thus decouples the frameworks from your appliaction and allowing application to inject interfaces and nothing else. This framework should be used instead of .Net Core IOptions<T>.
Make WPF and WinForms settings portable by saving them in the application folder. Read more at https://www.codeproject.com/Articles/1238550/Making-Application-Settings-Portable.
Shiny Push Integration - OneSignal