+1 My vote

..or any way to charge the battery without adding the USB shield.

Because you don't want to dismantle a smartwatch or your tiny console to charge it.

It doesn't really need to be a shield, it could just be a thing pluggable between the battery and the board (female for the battery, male goes into the TinyDuino).

µUSB (female) -> sending "inductor"
                                  |
                                   |
                                  |
                                   |
Battery -> receiving "inductor" -> TinyDuino board

It can be physically placed below the main board (or anywhere else really) with some tape.

Like the one I built here but "all in one". Because it's probably cheap and sometimes you like to add audio but just need a buzz