Gnote is described as 'note-taking application for GTK desktops. It is a port of Tomboy to C++. Gnote is part of the GNOME desktop environment, often filling the need for personal information management' and is a Note-taking App in the Office & Productivity category. There are more than 50 alternatives to Gnote for a variety of platforms, including Windows, Mac, Android, iPhone and Online / Web-based. The best alternative is Joplin. It's not free, so if you're looking for a free alternative, you could try Google Keep or Evernote. Other great apps like Gnote are CherryTree (Free, Open Source), Cryptee (Freemium, Open Source), Tomboy (Free, Open Source) and Notezilla (Paid).
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.
Notezilla is the leading sticky notes app for Windows, Android, iPhone/iPad and the web. Set reminders to sticky notes, Pin sticky notes, attach them to websites, docs & folders, sync between PCs and other devices, organize using folders and tags.