The best overall ad blocker for Safari right now is Adguard with "Use Simplified Filters" turned on. It blocks the most ads with the least issues. Now if you want the one that is most customizable then 1Blocker is the best choice. The best set it and forget it option is Adamant. The developer of Crystal is now accepting money from ad companies so their ads won't be filtered by Crystal. Now if you want one that blocks ads in apps too then you want Adblock by FutureMind. It is the only in app ad blocker on the AppStore that works on both WiFi and on cellular. The downside to Adblock is it uses VPN and it will not work with another VPN. It will for instance turn off F-Secure Freedome. My overall recommendation right now is go with Adguard, it's not only the one that causes the least issues, it's also ironically the only one mentioned that's actually free and with no iAPs.