As I've gotten myself a HP Elite X2 G3 tablet with an overwhelming amount of ports: 2 Tunderbolt 3s and one USB-C! So I wanted to get a docking station. I searched and found an auction for a Thunderbolt 3 docking station from Lenovo and as it uses the power supply I had lying around, I bought that for 15€ including shipping costs. It arrived and it worked for my Lenovo ThinkPad, BUT the great HP tablet refuses to charge from that! That's not what I wanted! So I though I would just send it back but after doing some research I found that people sell these stations for 50€ or more so I put it up for 50€ and not even 12 hours later I sold it. Pretty asshole move, right? But I got myself a refurbished HP docking station with a power supply for 45€ including shipping.
You can easily get these stations from HP or Dell used for 20€ but then they don't have the power brick with them. If you should find by any chance the right power brick by eyeballing the connector, well, you are either one of the luckiest people alive or you've created the docking station at HP or Dell. Lenovo at least used the same power connector for the last decade or so, so they are very easy to come by. HP and Dell didn't. (Applause!!!) Now, I'll see if the station from HP will charge the tablet.
TLDR: Sorry poor buyer, fck you HP (and Dell)!