It's becoming popular to overlay a gradient to give emphasis to more important areas of a character. (See DOTA2 style guide.) This script will take your object selection and apply a gradient in object space for each object and render it out to a texture. Your objects must already be unwrapped. If your character has a hat or other gear you'll want to combine the objects temporarily to get one map.
This worked on all the models I tested it on. But let me know if there are any issues.
To install drag and drop the MCR file into the viewport, then look in Customize > Customize User Interface > Keyboard > Category > monsterBlues.
BTW: This script doesn't actually apply any textures to your models. The screenshot above is to illustrate. The script will output and display a bitmap you can save.