[familytoad]

What era of cards do you collect, Dave?
And do you collect sets or target specific cards?

I have a spreadsheet with some prewar sets and the Topps era sets (included some Bowmans land some FB that I collect)

It does some very basic calculations on what percentage of every set you have/need and is very easy to filter.
If you'd like, I'll email the template version. Tell me what sets, and I f I have checklists, I will add them too.
It's nothing super tech, but it has helped me make sure I don't buy too many cards I already have, and easily see the ones I still need.
Add it to google docs and you have it practically everywhere you go mobile.