Wakelet - Awesome collections lovingly created by people
Raneto - Open source, flat-file Knowledgebase platform that uses static Markdown files
TagSpaces - TagSpaces is an open source platform for personal data management. With TagSpaces you can manage and organize the files on your laptop, tablet or smart phone.
HowHive - Knowledgebases for teams and companies of all sizes. Knowledge sharing and finding made simple.
Zim Wiki - Zim is a graphical text editor used to maintain a collection of wiki pages. Each page can contain links to other pages, simple formatting and images.
Obsidian.md - A second brain, for you, forever. Obsidian is a powerful knowledge base that works on top of a local folder of plain text Markdown files.