I wrote my own collection and inventory software many years ago, originally in dBase III+, migrating it forward as new versions came out. It never quite made it to Visual Foxpro (VFP), although I made several attempts at upgrades, and I still use VFP for many personal projects. But Microsoft made it clear that VFP’s days were numbered.
MS Access is probably the best choice for anyone wanting to roll their own. It imports and exports to many other software packages, and is easy to customize. For a single user, it is a great package, and likely to remain on the market until MS retires Office - which is not gonna happen.
Excel works but it has some severe limits as a database substitute.
If anyone is interested I would be happy to share the Access DB I’ve created for my own collection. It is naturally limited to my own personal needs and experience (and Access skillz), but you can’t beat the price!