There are 2 repositories under minecraft-chat topic.
bridge between mattermost, IRC, gitter, xmpp, slack, discord, telegram, rocketchat, twitch, ssh-chat, zulip, whatsapp, keybase, matrix, microsoft teams, nextcloud, mumble, vk and more with REST API (mattermost not required!)
An advanced chat plugin for survival/anarchy servers.
Connect your Minecraft in game chat to Discord!
Spigot server chat plugin for managing repetitive output such as join output.
Multi-server chat plugin for Velocity
Minecraft MoonLake Chat Lib
A plugin for Spigot servers hiding messages from players.
Simple Chat formatting plugin
A minecraft spigot plugin that allows you to custom your chat
A minecraft spigot plugin that allows you to custom your chat
Encrypt the Minecraft chat.
A simple Minecraft spigot plugin for generating gradients with hexadecimal codes that were added in 1.16.
Allows the minecraft chat length limit to be configured