The Elecjet AnyWatt is a great

“If you’re someone who’s made the jump to a newer MacBook Pro or other USB-C laptop and still have your old charger around, it’s a good way to get a spare on the cheap. Plus, if you’re someone who dislikes the fact that USB-C doesn’t automatically disconnect like MagSafe does, it’s also a hacky workaround to get that functionality back.”