Just figured I’d add to the thread that I was able to get the mini PCIe Coral working using the StarTech PEX2MPEX that @ukro had mentioned. My motherboard is the Gigabyte Aorus Z390 Pro Wifi and I’m running Ubuntu. Just needed to follow the instructions on the Coral website to get the driver installed.
Note for anyone else that adds this card with this mobo, after installing it and turning the power back on, the board flashed some white lights about 5-10 times over the course of about 30-45 seconds. During this time the machine would not boot - this cost me a lot of time being impatient. Just give it a minute, eventually you should see a green light on the PCI board turn on. The board should be ready to boot then.
I found the mini PCIe to PCIe board at Provantage for $33. It’s on Amazon for a few bucks more.
It required a small tweak to fit on the board though 
