I have an excel spreadsheet with several pages. The first page has everything I have ever bought and still own, broken between t206 and everything else. In different columns I list the player, the type of card, the back (advertisement/company), the grading company, the grade, when I bought it, purchase price, and from whom I bought it. Then I have several other pages/sheets that list different back runs and projects, all of which are already listed on the master sheet. I also have one sheet for cards I used to own, which has all the info of the master sheet, plus who I sold/traded it to, for what/how much, and the date.
I don’t have a huge collection - maybe 150+ cards - and I only acquire about 30 cards/year. All of my cards are 100+ years old and almost all have advertising backs, no card numbers; the only cards I have with numbers on them are 1914 CJs and M101-4/5s, and the latter have add backs too. So maybe my collection is easier to catalogue.
I have also catalogued everything digitally, on Flickr, kind of in same fashion, but with less info.
https://www.flickr.com/photos/156271...57676375209007