They are neutral footbeds, which means they don't fix either over-pronation or over-supination. If you pretend they are footprints left in mud, you can imagine the differences. Pretend you are putting your foot into a pre-made footprint made by someone with idealized feet.
Green: a footprint left in deep mud, deep heel cup and prominent arch "bump". Good for unstable feet (like an over pronator) or feet that get tired easily.
Blue: a footprint left in shallower mud. A shallower heelcup and less beefy arch. Good for folks who feel the green is too aggressive.
Berry and Orange: kind of between the blue and green, with the addition of a metatarsal button. Nice for "hot foot" or folks with a dropped met head/collapsed metatarsal arch. Or folks who put a lot of pressure on the balls of their feet (eg: cyclists)
Black and Gray: similar to the blue, but good for lower volume shoes like bike shoes or cowboy boots and some high-heeled shoes. (gray has a build that works well in high heels)
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson