One alternative I haven't seen mentioned is Glimmerblocker[1]. There may be good reason for this—it looks like the last commit was a few years ago—but I know it still works in High Sierra at least. However, it's been a long time since I used the program regularly.
Glimmerblocker is unique in that it doesn't use Safari APIs—it creates a proxy to filter traffic before it gets to the browser. Despite that, it's quite powerful; I remember using it to make an extensive Javascript patch for one site.
(I vaguely remember something about Glimmberblocker needing SIP to be disabled, but there's nothing about that on their website now, so I'm not sure. I keep SIP off anyway, so I wouldn't know.)
Glimmerblocker is unique in that it doesn't use Safari APIs—it creates a proxy to filter traffic before it gets to the browser. Despite that, it's quite powerful; I remember using it to make an extensive Javascript patch for one site.
(I vaguely remember something about Glimmberblocker needing SIP to be disabled, but there's nothing about that on their website now, so I'm not sure. I keep SIP off anyway, so I wouldn't know.)
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1: https://glimmerblocker.org