Through the course of creating Pokemon Dungeons' original artwork set, I had saved the linearts of the Pokemon artworks before they were colored.
These linearts are all available here as transparent PNGs for you to color or use as is or whatever. You can print out the linearts to color them or save them and color them in your image editor of choice.
However, there are some conditions for the use of these linearts:
If you create artwork by coloring these lineart, please credit Pokemon Dungeon.
Do NOT claim you created any of these linearts.
That said, have fun coloring these lines! I'd totally love to see what you come up with if you do color these, so feel free to let me know if you do color these linearts. Likewise if you are interested in colouring more Pokemon check out these Pokemon Colouring Books