Windows software

Note: some of these are free versions of pay-for software.

I know some of these are somewhat common but I included them anyway.

https://gyazo.com/
http://tixati.com/
http://www.cpuid.com/softwares/cpu-z.html
http://www.nexusmods.com/games/?
http://www.gimp.org/
http://www.displayfusion.com/
http://www.slysoft.com/en/virtual-clonedrive.html
http://www.sketchup.com/
http://niftools.sourceforge.net/wiki/NifSkope
http://www.videolan.org/vlc/index.html
https://www.google.com/earth/
http://www.xfire.com/
http://www.rarlab.com/download.htm
http://www.getpaint.net/
http://www.fraps.com/

Here are some alternatives to the listed programs:

VLC Media Player -> MPC-HC
http://mpc-hc.org/

WinRAR -> 7zip
http://www.7-zip.org/

Gyazo -> puush
http://puush.me/

Tixati -> Deluge
http://deluge-torrent.org/

Fraps -> OBS
https://obsproject.com/

Keep in mind my intention was not to list the very best kinds of these programs, only the ones that work in my experience.