I spend a lot of time dicking about with productivity tools to the detriment of actual productivity. Lately (as in for a large portion of this year) I have been using a handy script called nb to manage my notes.
It is absolutely bonkers how useful this thing is. Pulling from the website, it features:
Up until very recently I was using it as a dump for notes and links around my terrible gamedev projects and that's about it but I decided to start experimenting with the browse functionality. Suddenly my markdown notes solution sitting on a Raspberry Pi in my house has a mobile-friendly web interface!
Lately I've been using it to build out some documentation for my DIY PDA project with a bunch of links between all the different pages.
I cannot recommend this software enough.