Adguard. It was cheap and works well. System wide. Haven't seen an ad on a website or game/app in years.
Nextdns, private DNS that blocks requests to ad servers. You can use it on all of your devices.
Adaway for android is effective. It uses a pretend vpn system to block ads in apps and web pages. Does not need root.
RethinkDNS it's FOSS, the logs are detailed and easy to read, it lets you cut off internet connection for things that don't need it (i.e. Calculator), it can force connections to Orbot if you wish. Loads of different blocklists to choose from, or just use their presets for Ads, Social Media, Adult, whatever.
I've started to use trackercontrol. Mainly because it's not only for ads but also tracking in general. It reports which apps that contact what companies and it allows you to block them without root. And it's mainly made by the university of Oxford
NetGuard for android. It's available on google play and as a standalone apk that you can download from github. It can see all the url requests your apps are making. You can block an app entirely from the internet, or you can go through and manually block all the ad and tracking requests. You can also block apps from using data which is great if you don't have too much per month. You need to pay a small one time fee to unlock all the features though.
