EasyList Cookie: https://easylist-downloads.adblockplus.org/easylist-cookie.t...

AdGuard Annoyances filter: http://adguard.com/filters.html#annoyances

(There is also "Fanboy’s Annoyance", but it blocks more than just cookie notifications. For example, it blocks social media share buttons which I use a lot. So I don't use it.)