Two of the small tools we built for our own operation and put on our GitHub, because other people run the same hardware and hit the same problems.
Proxmox pool watchdog
An LVM thin-pool usage watchdog for Proxmox with a daily fstrim, wired to Discord alerts. A thin pool that fills to 100% freezes every guest on the host into read-only io-error, and it tends to happen quietly. This watches the usage curve and warns while there is still time to act, instead of after everything has already locked up.
Macro pad remapper
A remapper for the SayoDevice 1x3P macro pad: a browser UI paired with a small local Python HID agent, so it works from any browser without installing a desktop app. It's the kind of small quality-of-life tool that's annoying to live without once you have it.