One of my favorite tech/electrical travel hacks is this charging device that, using only ONE electrical outlet and the appropriate plug adapter if needed for the country you're in, can charge up to five electronic devices at the same time. I recommend that travelers get one of these type of chargers, and see how many of their electronic gadgets they can charge using it, and so they can leave unnecessary electric plugin pieces at home, and reduce the need for electrical outlets in hotel rooms. The charger isn't big: 4.06 x 3.15 x 1.14 in; it has a 5 foot long electric cord (removable for packing). It is dual-voltage, so in Europe you just need the appropriate wall plug adapter and it will handle the current just fine. It's in constant use at home and I always travel with it.
On this charger, my smartphone is charged using the odd-looking USB-C port, and the four 'regular' USB ports charge my: iPad, FitBit, camera batteries (via their charging devices such as this one), portable power bank, and headphone Bluetooth adapter. Obviously not all at once. I've rarely had all five ports in use at once but in a pinch I could. The only device I travel with that can't be charged using that charger, is my MacBook Air. This charger wasn't cheap, but it has a "smart" technology that figures out how to charge the things I plug into it, and it's never let me down.
The charger isn't marketed as a "travel" charger because it has a cord, which is a bit more to pack and carry. But that's just why I like it for travel - because you aren't stymied if the available electrical outlet in your hotel room is in an inconvenient place. Plug it in, and because of the cord you can place the charger and its attached devices, on a nearby appropriate and convenient surface (table, nightstand, whatever).
Recap: I travel with: (1) the charging device and its cord, (2) the necessary wall plug adapters for my destinations, and (3) the charging cables with USB (or USB-C) connectors for the various devices I mentioned. All of that fits in a smallish red fabric zip-close bag that came with a tote bag long ago. Many of the devices I carry, can be charged with the same cord (micro USB) so instead of bringing 3 or 4 of those I pack just two at most. My only devices that need charging every evening are the phone and the camera batteries.
And yes, I'm that person who has posted elsewhere, that my travel wardrobe and packing decisions amount to, whatever clothes I can fit in after the electronics are packed. :-)