The Miniware TS-100 is a cute little portable soldering iron. It can be powered off any 2.1mm jack 12-24v power brick, and I've had one since 2016 as i can keep it in my bag and have the ability to solder wherever i am.
I used to power it off a dedicated 12v wall wart, then i found a neat little lenovo 'square' to 2.1mm adaptor plug on aliexpress so i could use the laptop power brick i was already carrying with me, but since upgrading my laptop and going full usb-c i've not really been carrying anything thats been able to power the iron.
Miniware have since released the TS-80, which is a USB-C version of the TS-100. Great! The only problem is its designed for phone chargers, and so speaks QC 3.0. Given my phone and laptop both use the 'standard' USB-PD protocol (the same one used by all laptops, ipad pros, chromebooks etc), so i'd still have to carry another power brick around with me!
That was, until i found the ZYPDS USB-C "Power Trigger" - this is a tiny board that takes USB-C in one side, and does the protocol negotiation to ask for 15V or 20V out the other side, perfect!
So. ZYPDS board + 2.1mm jack.
Remove the outside of the jack, and snip the 'shield' pin so that its about the same length as the center pin. The TS-100 (and pretty much everything else that uses a 2.1mm jack) is center-positive, so solder the center pin to the + pad on the ZYPDS module, and the shield to the - pin.
Add a bit of heatshrink, and you're sorted! Soldering on the move!
This probably wont last particularly long, as its basically using the solder as a mechanical joint. If it fails i'll likely make another one by connecting the module to a short piece of flex, similar to my old lenovo to 2.1mm adaptor, but until then i'm happy with it :)