Dendron

Dendron is an open-source, local-first, markdown-based, note-taking tool built on top of VSCode. Like most such tools, Dendron supports all the usual features you would expect like tagging, backlinks, a graph view, split panes, and so forth. But it doesn't stop there - whereas most tools (try to make it) easy to get notes in, they tend to make it hard to get them back out later, and it only gets worse as you add more notes. Dendron helps you get notes back out and works better the more notes you have.