NetGuard
NetGuard offers advanced features such as network statistics, custom notifications, and rules backup.
NetGuard uses a local VPN connection to filter your internet traffic and allows you to block any app from accessing the internet via Wi-Fi or data. You can manage and create your own firewall rules for system apps.
You can not connect to more than one VPN because of Android limitations, so you can not use this app with any other VPN app.