I built an open-source antivpn connector for Minecraft (Velocity/Bungee/Paper)
I run a small server and got tired of the same few people hopping back in on a VPN every time they got banned. Plain IP bans do almost nothing once people figure that out, and the public lists I tried either missed half of them or kicked legit players (mobile users especially). So I started building my own thing and it turned into Jarvis.
What it does: checks players as they join and blocks VPNs, proxies, datacenter/hosting IPs, ban evaders and bot floods. I spent most of the time on the unglamorous part, which is not kicking real players, because one false positive costs you an actual member.
How it runs: a small connector plugin you drop on your network (Velocity, BungeeCord/Waterfall, or Paper/Spigot directly). It hands the check off to the backend, so it shouldn't add noticeable load.
The part I actually want to point at: the connector is open source, so you can read exactly what runs on your box before you trust it.
GitHub: https://github.com/JarvisAntiVPN/jarvisguard
I'm the dev and this is still a newer project, free to try right now. If you hit a false positive, open an issue. I'd genuinely rather hear about it than not. More at JarvisGuard.com.