The way things are supposed to be done.
Most services are halted due to current occupation at TBD.
Firefly is one of the most advanced anticheats ever created, it utilizes an intelligent alert system and features high customizable level while maintaining simplicity. The anticheat can detect 99% of all combat, movement, connection and world cheats while also preventing cheats from even being used. The anticheat does not require protocollib and is extremely light-weight while still being able to detect most of the cheats.
Price: 200$, Source: NFS
FireflyZ Anticheat NOT RELEASED
A version of firefly that adds support for 1.13.
Price: 200$(or 100$ addon), Source: NFS
Firefly Anticheat (Nano) NOT RELEASED
A light version of firefly that only blocks and detects essential cheats. This includes most of the combat and movement detections, however, ghost client detection is not included, which means it does not have checks for detecting aim, autoclicker, wtap and other cheats that are usually used by closet cheaters. This anticheat is designed for preventing people from blatantly cheating around your server.
Price: 20$, Source: NFS