this app is really good I have used it recently and its really proven useful. you can get it at the app store https://itunes.apple.com/us/app/adblock-for-safari/id1402042596?mt=12 They need to make macOS Mojave update for it.
Tarek, try just the Adguard extension, not the app. I have been using it for a long time, no problems.I have always used AdBlock and Adblock Plus on all my browsers across different devices, but I am currently looking for alternative blockers to try as well. Any recommendations besides uBlock? I just installed AdGuard and it seems to work well so far but I haven't had enough time to properly test it yet, and I don't know if it will end up being a memory hog since it's a separate app.