Would probably be smart to look into getting NoCheatPlus if you haven't... Some of the ones I know exist are: Flare, Ghost, BrainFreeze, Paralyzed, Metro, WeepCraft and Wolfram.... there are more.................. WizardHax is a site that has hacked clients....the ones mentioned above I have verified that do work..... On a server my brother is familiar with... and that he can't get banned on due to testing rights. Just a heads up!
Considering past work with Gorian's Tekkit server, and while I may not play much Minecraft/other related mods anymore and never really have... I would really suggest anyone running a server really look into anti-cheating plugins. And seriously do research on them. Minecraft is very tricky in regards to it's hack protection plugins unlike some games (DayZ I can through in infiSTAR and be good pretty much, Minecraft I can throw in a plugin and fuck up resources and FPS everywhere) so deffo do research. What many may say is a 'good' plugin can turn out to be one that will harm server performance significantly while there is another out there that works just as good/better without harming performance - so deffo research.