Ugly, but something like this plus a USB extension cable if needed? I guess you can take a small hair elastic and bundle the extra unneeded cables together. I'm also sure there's versions out there that are a decent color that can be more easily hidden than the one I link below.
https://www.amazon.ca/gp/product/B01...?ie=UTF8&psc=1
I think the term you can try searching is called "only charging" cables. Most cables that have multiple prongs on the end usually don't do data transfers "multi charging cable" is a search term you can use as well. Worst come to worst, these cables are excellent cables to pair up with portable power banks.