Open source softwares
I use the following open access repositories in my research:
R https://www.r-project.org/
GFortran https://gcc.gnu.org/wiki/GFortran
ED2 https://github.com/EDmodel/ED2
CESM http://www.cesm.ucar.edu/
NCL https://www.ncl.ucar.edu/
QGIS http://www.qgis.org/en/site/
C Sharp https://en.wikipedia.org/wiki/C_Sharp_(programming_language)
Linux https://www.linux.org/
SAGA GIS https://sourceforge.net/projects/saga-gis/
Perl https://www.perl.org/