External GPU Thunderbolt docks are *so* 2016. These PCIe x16 adapters will accommodate an MXM 3.x Type-A or Type-B GPU from either Nvidia or AMD for connecting straight onto a standard PC motherboard.
https://www.notebookcheck.net/Eurocom-MXM3-Riser-Cards-will-power-your-desktop-with-a-laptop-GPU.241042.0.html
Eurocom do the Thunderbolt 3 enclosure for the MXM cards!
https://www.reddit.com/r/eGPU/comments/66augw/mxm_egpu_the_portable_egpu/
Mantiz has been developing MXM Thunderbolt enclosure!
" MXM graphics cards are not currently sold as standalone products."
thi is not true :)
MXM GPU Resellers in the world
http://forum.notebookreview.com/threads/mxm-gpu-resellers-in-the-world.804197/
Successful MXM GPU Upgraded Laptops
http://forum.notebookreview.com/threads/successful-mxm-gpu-upgraded-laptops.805136/
That riser card is pretty much DoA compared to card with hbm.
Just look at new vega's pc bhttps://cdn.videocardz.com/1/2017/08/AMD-Radeon-RX-Vega-56-Prototype-4.jpg
SFF and mini computer would love those cards with hbm rather than you buy mxm and a riser card.