Mirror is a high level Networking Library that can use several different low level transports. To use a transport, simply add it as component to the NetworkManager and drag it into the NetworkManager's Transport field.
kcp2k - KCP Transport based on kcp.c, line-by-line translation to C#
Latency Simulation Transport to test non-ideal network conditions
Telepathy - TCP Transport - Simple, message based, MMO Scale TCP networking in C#. And no magic.
WebSockets - WebSockets transport layer for Mirror that target WebGL clients.
Multiplexer Multiplexer is a bridging transport to allow a server to handle clients on different transports concurrently, for example desktop clients using Telepathy together with WebGL clients using Websockets.
UDP - Ignorance Ignorance implements a reliable and unreliable sequenced UDP transport based on ENet.
Steam - FizzySteamworks Transport utilising Steam P2P network, building on Steamworks.NET.
Steam - FizzyFacepunch Transport utilising Steam P2P network, building on Facepunch.Steamworks.
Epic - Epic Online Services Relay transport utilizing Epic's free relay service.
LRM - Light Reflective Mirror Relay transport for WebGL clients.
OculusP2P - Oculus Platform Relay Transport for Oculus Quest 1 & 2.