Software engineers were some of the pioneers of the open movement. This GitHub page is a repositories of repositories – a great resource if you want to leverage code for some projects (Bootstrap, for instance). But there are also free books listed here as well.
Open source software for online shopping. You don’t need a lot of technical know-how to get this up and running, and the final product is pretty clean and sweet.
Inkscape is open source software for making illustrations and vector images. You can download this for PC, Mac, and Linux.
My Open Math is a tool for math educators that helps students learn – for free – with interactive tools.
Google has provided over 2000 open source projects, and this site shares all their work. This is exceptionally valuable to developers, but magnificently demonstrates the power of open to everyone.
Scribus is open-source Desktop Publishing software (it works on Windows, MacOS, Windows, and other operating systems). It’s been around since 2001, and is probably the most robust piece of open-source Desktop Publishing software available.