I use Consent-O-Matic. It doesn't catch everything but it does work on some sites. Basically it just automatically goes for the "Reject" option if that's provided in a reasonably standard way. Lots of sites where that doesn't work, obviously. But a few where it does.

Probably a good benchmark if you are developing standard cookie consent dialogs is whether they work with this.

I'm using "EasyList/uBO – Cookie Notices" in my uBlock Origin in the Filter lists. It works well enough for blocking cookie pop-ups.

We're working on this feature now! Privacy Badger will automatically opt you out of common cookie consent banners, when opting out is an option.

Not an exhaustive solution, but these are often loaded with third party requests. The domains often contain "cookie", "privacy", "consent", or similar, and blocking them does the trick. uBlock Origin lets you do that once you tick the "I am an advanced user" box.