Bedrock Edition server software

Unlike the official Java Edition server software, the unofficial Bedrock Edition server software usually lack many things that are present in Bedrock Edition vanilla server that are built into the Bedrock Edition’s client. The servers, excluding the official Bedrock Server Software, are also free of Mojang source code. In many cases, Bedrock Edition server software can outperform the official server software and can provide features beyond the capabilities of the vanilla bedrock server, like massive multiplayer experience. Unless stated otherwise, most Bedrock Edition server software are open-source, free of charge, and free-for-all use, including commercial use, given the license that's included.

Most Bedrock Edition server networks, including the featured servers, uses unofficial software as Mojang's official server software for Bedrock Edition has only been recently released and is currently in public alpha testing.

Official Server Software
On September 11, 2018, Mojang released an early alpha version of the official Bedrock Edition server software, Bedrock Dedicated Server, announced by Jeb on his twitter page.

3rd Party Mod Loaders for the Official Server Software
3rd party mod loaders always existed for BDS, they were just not well known by the community.

Most current popular mod loader with a proper api for C++ developers is Bdlauncher. Bdlauncher is currently developed and maintained by a few MCPE/Bedrock players from china. Github: https://github.com/Sysca11/bdlauncher. there is also one by MrMcArm: https://github.com/minecraft-linux/server-modloader

Comparison
This is a comparison of available custom servers for the Bedrock Edition of Minecraft. Servers that are listed here are required to have at least one publicly accessible release.

Proxy software list
Proxies allow transferring of players seamlessly between servers unlike the Transfer Packet.

Protocol Translator list
Protocol translators allow Bedrock Edition clients to connect to Java Edition servers.