I've used 'color scheme designer' [1], recently renamed 'paletton' [2], in the past. It has some of the specific features you are looking for, like darkened/lig

I've used 'color scheme designer' [1], recently renamed 'paletton' [2], in the past. It has some of the specific features you are looking for, like darkened/lightened alternatives of your main colors. [1] http://colorschemedesigner.com/csd-3.5/ http://colorschemedesigner.com/csd-3.5/ [2] http://paletton.com http://paletton.com