I heat embossed the image on black with white powder. I've had the powder forever and it wasn't expensive. Everything doesn't need to be expensive but I don't think the quality is present in this powder but it works for experimenting.
Hard to tell this is the same colored image but it is. The above photo is on an angle and closer to sunlight.
Next, I used the Pentel pens. Despite not being able to blend them the way watercolors will blend, I like this look on the black paper more than the above examples.
The Pentel pens were sold in a pack of 8 colors. I don't know if more colors are available that would have created better blends and shading, but these were fun to work with.