BasKet is an open-source note manager for KDE. With its comfortable, familiar interface and freeform notes, it's captured a loyal base of fans. However, the app is only for Linux and requires KDE, which might be a bit heavy for some users. Many lighter weight options can be found with the portable filter and the list can be narrowed down with Markdown support and integrated-search.
Alternatives for Mac and Windows are vast while some other great options hold their own for Linux. Some newer and bigger name note tools have managed to cover all those platforms as well as Android and iOS.
AllMyNotes Organizer is a multi-functional hierarchical information manager for Windows. Store all your Notes in virtual folders in one file! Everyone is unique so AllMyNotes Organizer offers freedom of individualizing your notes in totally customizable tree structure.
WizNote is a Note software, which is especially designed for Internet users and mobile Internet users. WizNote focuses more on notes of rapid collection, management, reading and sharing. WizNote is smaller, more stable, and more suitable for computers, phones and mobile devices.