Bluetooth almost got me 100% there as well! Until I discovered that Apple devices don't support sending/receiving files via Bluetooth. But at least it covers about 80% of the devices I own and doesn't rely on external services like most other options people wrote about as a reply.

Macbooks do; there's an app called Bluetooth File Exchange. Most people I know with iPhones have macOS laptops, too, so I can send to that.

Ah, sadly the 20% in the amount I wrote about above is one iPhone that won't play nice with the Bluetooth coverage I have at home with other devices :/