[aunty_helen]

I've been using uBlacklist which adds a little block this site button to the google search results. Handy.

It is a browser extension and I haven't looked too deeply into it so if that's important to you perhaps have a browse over their repo etc before installing.

[LordDragonfang]

If you scroll down on the OP, two of the source lists are actually uBlacklist block lists.

[OGWhales]

I use that too, great for blocking pinterest from flooding all of your google image search results.