I will be away for a while and sold my car. I might be in the US from time to time, and might rent or borrow a car at some point. So I needed insurance. But I don't own a car. Each of the insurance agents I talked to told me it was impossible to get insurance without a car. I explained to each of them that yes, it was possible. Each time they went and talked to someone else who showed them how to do it.
I ended up using Progressive, which is the company that I have my US motorcycle insurance through. Cost for $500K CSL, $198/year. You can only get liability this way, but collision insurance is usually through the owner of the car, but liability is usually through the driver.
Bob L