My Visual Database - Using My Visual Database, you can create databases for invoicing, inventory, CRM, or any specific purpose.
EagleData - Freeware database for Mac
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.
LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC
Standard Notes - A safe place for your notes, thoughts, and life's work
Kexi - Kexi | Calligra Suite