Power over Ethernet is a common method of charging using RJ45 cables connected to IEEE 802.3at compatible ports. PoE Texas makes an innovative adapter with this standard at one end and a USB output at the other. Its latest variant updates it to include a type-C port that can charge a high-end tablet or 2-in-1.
https://www.notebookcheck.net/PoE-Texas-new-adapter-can-bring-power-over-Ethernet-to-the-iPad-Pro-2018.434603.0.html