Google launched Coral mPCIe and M.2 cards at the very beginning of the year. The cards integrate the company's 4 TOPS Edge TPU used for low power edge AI applications to bring the solutions to boards with mPCIe or M.2 sockets.
Those are just hardware sockets that are optionally connected to USB, PCIe, I2C, etc... so you have to make sure the socket on your board exposes PCIe Gen2 x1. If you worry about compatibility, it's good to get a board that's known to work, and one of those is Gateworks Newport GW6903 SBC that offers two mPCIe sockets