Top 20 NuGet singleton Packages

ServiceCollection registrations for LazyCache to initialise the dependency injection collection and add enable IAppCache to be injected into your app
Common Core Classes (Registry, Files, etc.
Ninject module regististrations for LazyCache to initialise dependency injection
Acorisoft.LiteDB - A extented library for LiteDB,you can use it to make your work easy and handy Acorisoft.LiteDB 是一个Lite DB扩展库,你可以通过使用它来快速获得数据库单例对象。
A .Net library for code simplification.
AmbientScoping
Common library for registering any component using ISingletonDependency, IScopedDependency and ITransientDependency
Simple singleton for reusability.
Provides an easy way to implement the singleton (anti?) pattern so that it is ambient-safe, propagates with a call context and can be overriden per ambient (i.e. in tests).
xUnit tests for netfx-System.AmbientSingleton
An assembly containing class[es] for managing and using singleton instances of reentrant objects.
TecLimit Essential Patterns Library
TecLimit Security Crypto Library
EZCache allows you to cache various types of items in caches that are configured for each cached item type, using a simple fluent API. Each item type cache can be configured to be singletons, or multi-instance caches. Items in the cache can be preloaded, set to expire, auto-reload, mark...
Bussines logic encapsulation framework.
A singleton logging component. Simple to use, lots of flexibility. Writes to a user-specified log and path, and optionally sends email. Can also write logs to a SQL Server database, with optional audit log. T-SQL files included. For .NET Core 2.0+, .NET Standard 2.0+, .NET Framework 4.6.1+
LinksPlatform's Platform.Singletons Class Library
Applications: console, singleton, service host, timed. Service host installer.
Generic template for implementing Singleton Design Pattern.
Singleton Wrapper for log4net