Joplin - 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, tagged and modified either from the applications directly or from your own text editor.

Tree Notes - Simple, clean and light-weight notes manager. Organize all your notes in a tree structure with icons.

OneNote - Get the OneNote app for free on your tablet, phone, and computer, so you can capture your ideas and to-do lists in one place wherever you are. Or try OneNote with Office for free.

Halna Outliner - "Halna Outliner" is an outline processor that has Two panes, one for Tree part and one...

Standard Notes - A safe place for your notes, thoughts, and life's work

E-Z Contact Book - E-Z Contact Book is an easy to use yet powerful Windows application for managing contact information. You can use it as a personal contact address/phone book, business directory, or a customer database, or a reminder of birthdays and other events