I've had $100k through Eastern Insurance for a few years now. Covers your shit anywhere, in the mail, at a gunsmith, in your house, etc. Even covers reloading items, optics, etc.
I pay $333/yr for the $100k "Unscheduled Blanket Coverage) with a $250 deductible. This reflects the NRA member discount. No need to give them an inventory or anything except for any single firearm over $10,000.
They do offer Scheduled Coverage but for $333/yr for $100k coverage I felt no need to explore that policy knowing I'll have to list and catalog everything.