Diy test equipment collection thread

Hello everyone if there is a thread already like this one I apologize and maybe some kind soul would link it here? 🙂 If there isn't one , maybe we can start one and pin it?

I am looking to start a thread where we can collect smart/nice to have DIY equipment that will help with Everything that comes close to DIY Audio. Or just a fun little project to build. Then when there is a lot of them , we can make a poll and get a top 10 most useful or something 🙂 just post whatever good threds you can find so there can be a big collection of them 🙂

this one is usfull
Simpel no math transformer snubber test jig
https://www.diyaudio.com/community/...rmer-snubber-using-quasimodo-test-jig.243100/