The Surface Dock will add plenty of ports to your Surface Pro 6

[Windows Central]

Best answer: The Surface Dock, connected with the proprietary Surface Connect port, will certainly work with the Surface Pro 6. Lack of USB-C and Thunderbolt 3 on the Pro 6 means you can't use more modern docking stations, but you'll still get plenty of extra ports and it will charge your Pro 6 while connected.
Amazon: Surface Dock ($126)

Full story from the WindowsCentral blog...