There are 2 repositories under minecraft-anti-cheat topic.
Anti-cheating plugin for Minecraft (1.5-1.20, Bukkit/Spigot)
Scythe AntiCheat - The best minecraft bedrock anticheat designed for realms, worlds and servers
The free anti-cheat since 2016
A List of Minecraft Anticheats
The best minecraft bedrock anti cheat with strongest detection. It's a realm anticheat mainly.
This anti cheat uses the Scripting API to fight some weaknesses in Minecraft: Bedrock Edition
The best free anticheat for minecraft bedrock edition
A backup source for Minecraft PVP-focused client made by LEF-ganga (aka ImFlowow)
Minecraft Computer Anticheat tool for basicaly any system and server admins - by cosita3cz#2095
The most advanced Minecraft Bedrock anti-cheat solution
A Minecraft Launcher Information Checker
Scythe AntiCheat - The best minecraft bedrock anticheat designed for realms, worlds and servers
An official Reflex add-on for better autobanning.
A simple lightweight Reflex add-on that allows to disable certain check's components at runtime using simple Bukkit commands.