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There are lots of domains (like Wikia) I want to block 95% of the time, but don't want to totally block, in case I need them as a last resort.

Also many of the worst offenders seem to be spam sites with unique URLs. Too many for me to individually make a dent.

Kagi may interest you then:

For a given domain, you can select: block, lower, normal, higher, and pin to help you rank results on your personal preferences.