Free
[Subject to Change] To my knowledge this tool is free, and/or Open Source in some cases. You can use most if not all of the features of this product.
Tangent Notes
Tangent is designed to let you write the way you think. Your thoughts are connected; Tangent lets you link to existing notes and make new ones with ease.
Dendron
Knowledge Management. Redefined. Lightning fast. Open source. Built to scale.
Bangle.io
Bangle.io is a powerful yet simple note taking web app that works on top of your locally saved Markdown files.
Anytype
the everything app for those who celebrate trust & autonomy!
SiYuan
Privacy-first personal knowledge management system that supports Markdown, block-level ref, and bidirectional links
