software

GOOD:
inkscape
libreoffice (nowadays)

openbabel is ok.

BAD:
blender sucks very much for how overhyped it is; yeah you can do anything, if you're willing to suck your soul dry.

gchempaint is shit, crashes randomly and very constraining.
bkchem is better but still kinda sucks.

GIMP SUCKS DONT USE IT