>>8648042
I have an Excel sheet which I have been updating for 10 years+.

Now I also use LANraragi. Its a local web server for archives (zip) and such. It can download from ehentai and some others or if you already have the zip of doujins, it can fetch the tags.

You can create categories and I could use that for "in collection" or "want to buy" but I only use it for doujins I have.