Blokada is an ad and surveillance blocker for Android. Sets up a virtual VPN connection (so it doesn't need root) and filters all outbound connection requests. Works at the OS level so you don't have to plug it into a bunch of your apps.
Github: https://github.com/blokadaorg/blokada
F-Droid: https://f-droid.org/packages/org.blokada.alarm/