uBlacklist

This extension prevents the sites you specify from appearing in Google search results.

You can add rules on search result pages, or on sites to be blocked by clicking the toolbar icon. Rules can be specified either by match patterns (e.g. *://*.example.com/*) or by regular expressions (e.g. /example\.(net|org)/).

You can use this extension in several search engines other than Google. The list of supported search engines is available at:
https://github.com/iorate/ublacklist#supported-search-engines

You can synchronize rulesets across devices via cloud storage. At the moment, Google Drive and Dropbox are supported.

You can also subscribe to public rulesets. Some subscriptions are listed on the website:
https://iorate.github.io/ublacklist/subscriptions

Usage:
https://iorate.github.io/ublacklist/docs/getting-started

Changelog:
https://github.com/iorate/ublacklist/releases