What always annoyed me about the molds in Angband was that they are just named "$COLOR mold." And once you've seen a blue one, you know without even meeting them that there's got to be a yellow one, a red one, a brown one, a green one ..... because once they start using color names in Angband they feel some strange and oh-so-predictable obligation to complete the whole set.
Your molds look to me like a nice underwater pic of some kind of seaweed. What did you use to do the images?