I'll start by saying that I know this probably swings slightly out of bounds for 1P, but since it's become such a ubiquitous tool for so many of us users and power users, I think it could be a huge benefit for many of us, and even the general user crowd...
I have an app called Compartments which I picked up a couple years ago either in the MAS or perhaps a bundle. The dev no longer has it on their site, and the MAS says it's no available in my country in order to update. Most-importantly: there's no sync method. The purpose of the app is to keep track of items you own, from jewelry to vehicles to appliances and so on. It keeps pics of product/labels, and has fields like 1P for serial and model numbers, purchase date/price, registration info, and keeps things gathered by "rooms" which could be handled easily by 1P tags, if necessary at all (it's not for me).
The category could be "Things" or "Purchases" or whatever you decide, but having a simple way to not confuse them with other things would be ideal. I just used the Membership category to store the pic of the label from our fridge and then added the purchase date, build date, serial number, and model number. I will probably use this category until another becomes an option. Fwiw, I tried to use the Document category to add a new item, figuring I could base it upon a pic of the product or the label, but it says that this category isn't available for my chosen vault. I don't know if the vault needs to be upgraded or my app does, but seems odd that the app would show a category if it couldn't make use of it.
My thinking is still better leaning towards the idea that we store this info in 1P instead of having another app dedicated to only one thing and also which doesn't have sync. A proper use case would be at a store and remembering we need new filters for the fridge water or ice machine, and pulling out a phone to check the model number to ensure they purchase the proper filter model. Heck, we could and should save the filter model right there with the entry and save another step. ...
I just took two mins and saved the filter and water inlet valve part numbers that we just replaced there with the entry. Might not even be a bad idea to have a notes-type field where you could log service records (water filters, oil changes, tire rotations, furnace filters)? That's handled easily enough in the notes field, but if the category was being created for this purpose, might as well include it as a field type.
Any chance this could end up on the roadmap?
1Password Version: 7.7
Extension Version: n/a
OS Version: macOS 10.14
Sync Type: iCloud