Asklemmy

I am going to argue Swiss type J.

It’s compact, safe, and easy to use.

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.

https://en.m.wikipedia.org/wiki/IEC_60906-1

I'm always up for a bit of controversy. I like the basic ungrounded American plug (NEMA 1-15).

It has no safety features. Just about every American has shocked themselves with it once, but very few have done it twice. I like it because it's compact, and that leads to some conveniences:

• It works great in folding designs for portable power supplies. I've seen folding implementations of Europlug and even British plugs, but they're not as compact.
• It works great for ultra-compact splitters and many-outlet power strips. Yes, you can be dumb and overload these, but we have a whole lot of low-power electronics in the modern world such that it's not hard to have a dozen devices each pulling less than an Amp. Multi-port USB power supplies are starting to mitigate this a bit.
• It doesn't have shutters (by default), so it's easy to plug things in. Every plug type I've encountered with shutters takes a lot of force and sometimes binds.