I guess you aren’t totally familiar with the units, but volts ARE a metric unit. A volt is one joule per coulomb. A coulomb is a unit of electrical charge equal to the amount of charge that flows through a conductor each second if that conductor is carrying a 1 ampere current. A Joule is a unit of energy. It is equal to 1 newton-meter. A meter is obviously metric. The newton is a force unit, which is equal to the force needed to provide a 1 kg mass with an acceleration of 1 meter per second per second. Thus, newtons are also a metric unit. Therefore, volts are metric.
For a similar unit in the imperial system, you would have to use energy in imperial units per unit of electrical charge. The force unit in imperial is pounds (we usually mistakenly consider pound to be a mass unit; it is not). Distance is in feet, so energy is in foot-pounds. Assuming coulombs are still used for charge, we would have foot-pounds per coulomb as the imperial unit for electical potential. Obviously, I have never seen such a unit used.
That was humor. I'm an electrical engineer.