Limited sets of limited colour volumes

Here are a couple. When you get one of these small packs of felt-tips, and you're mainly doing portraits, you easily work through the more obvious skin colours, such as the maroon-orange-yellow of the second picture here. So, and you've seen this elsewhere as well as in the first picture, I've started monochromes with colours like blue and green. Now, when I decide to start with landscapes, I'll find that the greens are all gone...