Google analytics and Google fonts are regularly enforced, but not by data protection officials. "Enforcement" of those is, as you've said, done by scummy private lawyers, scanning websites and sending expensive letters ("Abmahnungen") en masse. Basically, due to a weird precedent, those lawyers are allowed to give you unasked advice on your wrongdoing and billing you for it. But that is, afaik, a specialty of German law, and mostly limited to stuff that can be fully automated. So while you can scan for a website using Google Fonts, you cannot as easily scan for someone using Office365. Although you might, maybe, get a hint by looking at the DNS MX records.