I used to draw years ago and I really liked to sketch using pencils with colored lead instead of graphite. They had a softer feel than lead pencils, didn't smudge as easily, and could be easily erased, unlike traditional colored pencil. These are the pencils used in illustration that commonly come in black, red/orange, and blue, although there may be some other common colors. They aren't meant to be used to color in anything, rather they are used instead to stand out from one another when doing outlines and basic shading techniques.

I think the purpose of these pencils is to allow doing rough outlines in red/blue and then a final outline in black, with only the black showing up after the other colors are keyed out.

What keywords do I use to locate these special kind of pencils? They are literally colored pencils but not the same as traditional "colored pencils."