Boostnote is described as 'An intuitive and stylish markdown note app for developers. It's fully open-source' and is a very popular Note-taking Tool in the Development category. There are more than 100 alternatives to Boostnote for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and Android. The best alternative is Joplin. It's not free, so if you're looking for a free alternative, you could try Standard Notes or Microsoft OneNote. Other great apps like Boostnote are Obsidian (Free Personal), Notion (Free Personal), Google Keep (Free) and Evernote (Freemium).
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.
Joplin vs Boostnote opinions
pros, cons and recent comments
Joplin syncs with mobile seamlessly only bad side is it doesn't have syntax highlighter for code notes.
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.