Before anyone says UK I’m going to say they’re too bulky to be worth it. A usb charger for a UK plug is just so big and bulky that it’s not worth it. The Schuko plug falls into the same category.
If we are allowing future potential plugs I would argue for IEC 60906-1. It’s basically the same as Swiss type J but with very minor changes.
Swiss is interesting. It lacks some of the inherent safety of the SchuKo style, but it's also far more compact, while keeping most safety features. I guess it's a good compromise, which is often the crown achievement in engineering anyways.