I have started but not completed, an image database of bikes including serial number (or any stampings, not all have serial numbers) for potential recovery in case of a loss.

As to a spreadsheet.... I have kept a service book on many, that's it. To treat is like a business inventory would just take any fun out of it. Or reduce my surprise when I found that extra set of NOS Campagnolo pedals or extra seat post. Every frame needs a seat post...

I did take a big swipe at organizing my stuff... I am glad there are spare offices at work to store stuff.