My Visual Database - Using My Visual Database, you can create databases for invoicing, inventory, CRM, or any specific purpose.

EagleData - Freeware database for Mac

LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC

Zim Wiki - Zim is a graphical text editor used to maintain a collection of wiki pages. Each page can contain links to other pages, simple formatting and images.

Symphytum - Symphytum Project

CherryTree - A hierarchical note taking application, featuring rich text and syntax highlighting, storing data in a single xml or sqlite file.