I think the most common color was Black blue or dark blue, as the name says a very dark blue tone.
Other possible colors, Feldgrau #2-3, olive green. The Wehrmacht used more green or brown camo
on their vehicles, especially on vehicles in front use. The Kriegsmarine had not such great need for camouflage.
Image of a car belonging to a Kriegsmarine propaganda unit.
Restored Mercedes from the Kriegsmarine High Command.