Ditto on Inland Marine. My dad was an investment broker and had a partnership in an insurance agency that catered to high end clients and Inland Marine was used all the time for things like this.
When I lived at home we had our collection insured under one as well as I have mine insured under one right now. Inland marine is also useful for certain types of jewelry, art, collections etc...
My dad had clients that used Inland Marine for things like pianos, golf clubs, tools for guys with woodworking shops in their house, wine collections, one guy had a home beer making hobby with all the equipment insured, and on and on.