SiYuan is described as 'desktop Markdown Block-Reference and Bidirectional-Link note-taking application' and is an app in the Development category. There are more than 10 alternatives to SiYuan for a variety of platforms, including Mac, Windows, Linux, Self-Hosted solutions and Online / Web-based. The best alternative is Joplin, which is both free and Open Source. Other great apps like SiYuan are Obsidian (Free Personal), Standard Notes (Freemium, Open Source), Typora (Free) and CherryTree (Free, Open Source).
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.
Zettlr is a supercharged markdown editor that combines many writing editor features and collect them in one application. It aims at speeding up your workflow and help you write without any interruptions.
As easy to use as a word document or bulleted list, and as powerful for finding, collecting, and connecting related ideas as a graph database. Collaborate with others in real time, or store all your data locally.