It’s mostly family photos and videos. I’ve become the de facto family digital archivist. Some digital copies of important phyiscal records. When you convert files to lossless/uncompressed formats suitable for long term storage they get large really quickly.
I use BD-R for archival storage of important files. They’re cheaper and easier than tape as well as small. I burn them in triplicate and throw them in the same case and as long as the same 3 bits don’t corrupt I can recover. The shelf life on a blue ray sealed and stored well is a few decades which is better than most other media.
Godspeed.