1. LibreOffice
It doesn't matter who you are nowadays probably at one point or another you have used Microsoft Office. It has pretty much become the standard for word processing software, but with one downfall it’s not free. This is where LibreOffice comes in not only is it entirely free it is also cross platform including support for Windows, Linux, and OSX. LibreOffice has almost any feature you can think of that Microsoft Office has and it’s one of the most powerful free open source office suite in existence.
2. Github
Github is one of if not the best development platform to host code, build software, manage projects, and all along side other developers for free. It includes website support, great version control software, and command line tools.
3. Google Chrome
What more can you ask for from a browser than multi-platform support, account bookmark and extension syncing, and having it all on every device you own including your mobile devices.
4. GIMP
GIMP is an amazing cross-platform image editor available on Linux, Windows, OSX and more. It essentially is the free and open source version of Photoshop with numerous features and 3rd party plugins for all your photo editing needs.
5. Notepad++
Notepadd++ is one of the best free Notepad replacements. It supports various programming languages, file encoding, and a crazy amount of plugins. It is everything Windows Notepad wishes it could be.