I’ve used Taiga and Kanboard and both are pretty good

Government auctions and LabGopher

I wish I had data that could fit on an SD card - I too don’t have off-site backups mostly due to expense. I have one other friend that is into homelabbing but for us to each backup on each other’s hardware would be ~$2k/each. Probably more on his end because I believe he’s using a consumer NAS without the room for additional expansion whereas I have a 25 bay commercial setup that’s only 1/5 populated at the moment