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.

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

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

Symphytum - Symphytum Project

TiddlyWiki - a non-linear personal web notebook

PortaBase - PortaBase (portable database) is a program for conveniently managing one-table database files.