Anti-Cheat... What's everyone using?

Create your own. Every server is different. You have different needs, different gamemodes, different resources, different expectations, different everything.

Have a read through How To Create an Anti-Cheat - List of Vulnerable and Abused Events (Updated January 2020)

Also add the usual detections applicable to your server gamemode; invincibility, allowed weapons/vehicles, ped models, detect illegal commands and so on.

Reminder to also never ever buy an Anti-Cheat. Not only is it against the ToS, they are often extortion resources and are completely capable of making yourself.