Intrepid
Free and open source note-taking app for macOS, built on the Chronicle file format.
Download alpha for freeView on GitHub
Features
Asset management
It's all Markdown but the Chronicle .crncl file format bundles all images and assets to make sharing files convenient.
Outline thoughts
The sidebar is populated from your heading structure and lets you quickly jump around the document.
Smart blocks
Embed YouTube videos, bookmark any link to see rich previews and write KaTeX math.