By convenient I mean the one that won’t shove pop-ups with questions and pleads to rate it down my throat constantly. Can I find something like this?

Ah yes. I can relate to your frustration. But it isn’t the only thing I can do here Here’s the add-on you need https://chromewebstore.google.com/detail/quick-color-picker/mmjhombiehngfpipefodkebphfnblphe . No ads there and no pop-ups. And what’s even more rare color picking is actually working properly.