Gluttony: Parasite’s a good choice. At the moment, I can’t really think of another one.
Lust: Psycho’s a solid choice. Maybe Star Sapphire when she’s in crazy forehead-gem mode. Depending on how the sins work, Zeus actually may be the best candidate.
Greed: I always sort of assumed that the sins were limited to Earth (and there might be equivalent beings on other worlds, but they seem so obviously derived from human mythology), so for the sake of argument, I’ll actually put Vandal Savage here. He wants to take over the world. How much greedier do you get (unless you’re Larfleeze)? I’ll also throw Parallax!Hal Jordan out there. He blew up the Green Lantern Corps for not giving him what he wanted. Now, you can’t blame him for being grief-stricken and trying to rebuild Coast City, but it was unreasonable to take out his anger on the Corps for stopping him. That said, I don’t think it makes much sense for him to be possessed by two demon monsters at once.
Pride: Grodd believes himself superior to all of humanity. I think he’s a pretty good fit for pride. Alternatively, there’s the retcon that Raven is an embodiment of pride (which actually doesn’t fit her original characterization all that well), so there’s her, but she’s not (usually) a villain.
Wrath: I’d pick Doomsday, even over Atrocitus. His entire mind is nothing but rage.
Sloth: This is a rough one, because there aren’t many villains particularly noted for their laziness. I’m not really sure about the Turtle; he’s slow, but reasonably motivated. I guess Abra Kadabra came all the way back from the distant future with incredible advanced technology to the point that it’s indistinguishable from magic… and uses it to rob banks.
Envy: Honestly, a lot of heroes has a strongly envy-driven villain. Luthor’s a borderline case (you could say he’s motivated as much by pride or greed depending on the interpretation), but there’s Superboy Prime, Hugo Strange, Hush, Veronica Cale, sometimes the Cheetah, some versions of the Silver Swan, Professor Zoom, non-professor Zoom, Hector Hammond, Ocean Master, Doctor Sivana, Count Vertigo sometimes, and probably numerous others if I thought about it enough. I’m picking Superboy Prime, because he seems to be motivated to the most drastic measures by his envy of other people having an Earth.