I will answer all of these from a breeders point of view.
This female is a very nice one. The only flaws I see on her is that he caudal looks uneven and is a bit rounded. It's wider on the top half. Also her anal fin is shorter than most of which I've seen. That's not a huge deal though so overall she is really nice. The wide dorsal is very nice and really good for breeding. As nice as she is, I personally don't think she's worth that much. Not even a pair should be more than $60-$65 (not including importing). I would hold off on her.
A marble dragon
Now this female is nice As well formwise. Also the same reasons. Looking for wide dorsals are very ideal and benefitting. Though that female's caudal doesn't have the full 180 spread. She is also priced reasonably.
Well she is most definitely a female. She looks to be a very fascinating female because of her thickened body. Her wide dorsal is one of my favorites as well. The caudal is what bothers me most. It's also uneven just like the first female's. It's wide on the top half? The caudal is also just a bit smaller than is should be. That's not a bad flaw or anything. She is overall a very nice breeder. Good price on her.
Fancy koi. Says it is female, but I have doubts.
Yes. This female's anal fin Is long. Too long for my taste. I really don't like to see HMs with long anal fins because in my own personal opinion, it throws off the entire fish and looks to be a big flaw in the fish. Her dorsal almost looks like she is a DT geno. Reasonably priced.
Red dragon HM. I think her anal fin is a bit long.
I Personally don't like this female very much. Her caudal is very uneven. It's wide on the bottom half and taller on the top half. She would make a nice pet, but IMO, not breeding quality. I'd stay away from her, though the price is reasonable.
Black copper CT.
This is a male
. IMO a nice one, but he does have a few flaws. His anal fin is uneven. The farther back side (closest to the caudal) is Shorter than the front half (closest to his Ventrals). His dorsal appears to be messy, but a look closer looks fine. I really like CTs and this male looks very nice both in color and form.
I really like your choice of fish. Some are better than others of course, but looking for wide dorsals and even fins will get you very far. From what I said about these females and male, you should be able to tell what to look for if you choose to still look for more.