The review of Gpick mentioned that you can drop colors from Gpick to either Inkscape or GIMP. What it doesn't mention is that you can freely drag and drop colors between those three applications.
This is an introduction to creating harmonic color schemes with Gpick, an advanced free color picker
A new version of standalone advanced color picker Gpick is out with several considerable improvements.
New version of color picker Gpick is out with new features and fixes.