If you don't know, I will inform you that seeds do not come true to parent plants. So, although you may buy seeds from say, a Gina, that's not what you will get. It could be any color and it will be a one of a kind plant. Even if you get lucky and one comes out very "close" to the parent, that's not what it will be. That being said, you can buy whatever seeds you like and still get something very unique. It doesn't have to be from a specific named variety. I don't typically buy seeds personally, but I purchased some off Etsy a few years ago and had a high success percentage with them.
to the plumeria forum! 
with Jason, plumeria does not come true to the parent.
