Is anyone aware of a z3c.form field implementation for HCaptcha or even working on something related?
Interesting, didn't hear from hcaptcha yet. And recaptcha is out of the question nowadays if you want to be GDPR compliant. Any page with a recaptcha is a data trove for Google.
According hCaptcha's homepage hcaptcha "is a drop-in replacement for reCAPTCHA: you can switch within minutes." and we have https://pypi.org/project/plone.formwidget.recaptcha/ .
Looks interesting. Shouldn't be too hard to either integrate it into p.f.recaptcha or build p.f.hcaptcha.