Top 20 NuGet websocket Packages

Streams for full duplex in-proc communication, wrap a WebSocket, split a stream into multiple channels, etc.
Client for websocket API with built-in reconnection and error handling
WatsonWebsocket is the EASIEST and FASTEST way to build client and server applications that rely on messaging using websockets. It's. Really. Easy.
Chilkat .NET Class Library (64-bit) for SSH/SFTP, FTP, CAdES, XAdES, REST, POP3, SMTP, IMAP, SSL/TLS, Zip, REST, OAuth2, HTTP, RSA, XML DSig, Encryption, Compression, XML, Socket, XMP, HTML to XML, JSON, JWT, OAuth1, conversion, PKCS12/PFX, Java Keystore, ASN.1, PEM, ECC, Async, ...
A self-hosted, easy to use realtime database
SDK for www.CoinAPI.io WebSocket API
Chilkat .NET Class Library (32-bit) for SSH/SFTP, FTP, CAdES, XAdES, REST, POP3, SMTP, IMAP, SSL/TLS, Zip, REST, OAuth2, HTTP, RSA, XML DSig, Encryption, Compression, XML, Socket, XMP, HTML to XML, JSON, JWT, OAuth1, conversion, PKCS12/PFX, Java Keystore, ASN.1, PEM, ECC, Async, ...
The Diffusion .NET Client Library allows interaction with a Diffusion server from any environment that supports .NET Standard 2.0. Clients use a WebSocket connection to send and receive, as well as perform other functions such as adding, removing or updating topics.
WebSocket4Net is a .NET websocket client implemtation. It originates from SuperWebSocket WebSocket Client. For better developing of the websocket client, it was separated from SuperWebSocket and was renamed to WebSocket4Net.
This is the dll found in 1.0.3-rc11 of the original project, although it is not flagged as prerelease by NuGet which should allow using it as a dependency without flagging your own library as a pre release.
WebSocket Protocol library and server extension for Twino Server
Redis sync module for SapphireDb
High performance WebSocket on .NET Standard 2.x/.NET Core 2.x+ (both server and client - standalone or wrapper of System.Net.WebSockets.WebSocket)
High performance WebSocket on .NET Standard 2.x/.NET Core 2.x+ (both server and client - standalone or wrapper of System.Net.WebSockets.WebSocket)
The client module for a simple websocket server and client implementation with authentication using Kestrel middleware.
Twino Serializable Model library for object based communication with text-based protocols
Twino WebSocket Client to connect all WebSocket servers
Simple, lightweight, yet powerful way to build reactive, real-time web apps. SignalR hub for ASP.NET Core.
Simple, lightweight, yet powerful way to build reactive, real-time web apps. Library for .NET Core.
Connectors for twino WebSocket and TMQ protocols