Little Snitch - Little Snitch is a firewall application that monitors and controls outbound internet traffic.
AdBlock - Ad blocker for Chrome, Safari and Opera on desktop and Safari for iOS devices.
NetGuard - NetGuard
RethinkDNS - 2B+ Android users deserve access to a safer and open Internet.
Portmaster - Is a Privacy Modular Privacy App which includes a "DNS over TLS" feature as well as an "Application Firewall".
Blokada - The best ad blocker for Android. Free and open source.