Been really liking the concept behind the First Wave universe, a blend of classic pulp literature (and the Spirit) and a more Golden-Age DC Universe. Would love to see more of this universe. But I can't help but wonder... 
 
who would make great additions to this universe??
 
The original Spy Smasher would make for some neat stories. I'd envision it as a sort of James Bond-like approach, though more closer to the Bond of the original Fleming novels than the version in films.  
 
The Challengers of the Unknown would be well at home in this universe, as their adventures were usually more pulp-themed. I'd envision it like a mixture of Jules Verne, Sir Arthur Conan Doyle, and H.G. Wells through the filter of pre-50's sci-fi movies, b-movies, and serials. It would give them some much-needed attention. 
 
Who do you think would make for good additions??

I think its sad that no one answered this. I know First wave is cancelled but for fun I'm going to throw my 2 cents in. I tried doing a little research for this to have a reasonable answer.

I. some already existing characters. I looked up a few DC oldies and non DC characters they could acquire. I tried to stick with a 1940s-50s pulp noir genre/ ideal. 1 have to say Rocketeer. He was made in the 80's but was an homage to the 30s-40s. I think he would fit in perfect with Doc, Batman ,and Spirit.

2 I know the Blackhawks made an appearance in the First wave universe but i think they could have held there own title . showing them in that eras styles and tech would have worked.

3 Solomon Grundy I think would have made a good villain to appear. I can easily see him fighting with Bats,Doc and Spirit.Even Rocketeer as i mentioned above.

4 Sandman. Sandman is a pulp character in general so he would fit in.

5 The shield. He's a captain America type character. DC has already done a few interpretations of him. Newer looking pics of him look great So I could see him being like the lighter side of the 40's. He would represent The American ideal of the time Maybe be kinda blind to the dark and grunge that some of the other characters have to face.

6 Lady Phantom. I personally don't like her powers and have read a few story's of her and didn't like them. But dam is she FINE. She originated in that time and she is good looking. So I think if they tweaked her powers and personality a bit she could work. Would ad a woman to the universe.

7 Black Terror. He's a name i think a lot of people recognize even if they don't actually know much or anything about him. Hes been redone so much DC wouldn't necesarly stay true to the character. I think would they should do is keep his original appearance style minus the cape and get rid of the "gas powers" make him a vigilante punisher style character. he would be able to have conflicts with the villains and heroes that way.

8 captain Battle. Found him doing the research hes basically just like the Rocketeer uses a jet pack to around and whoop some ass. Except Cap Battle was created in the 40s and Rocketeer was created in the 80s. From what I read Rocketeer is a almost the same thing and possibly a rip off. so what I'm thinking for this character is instead of being a hero he could be a torn individual. Like say he was a famous hero Early in time in the First Wave universe. But then Rocketeer came a long (In Caps mind a clear rip off of him) and stole the spotlight. Cap thinks he stole everything that should belong to him. So he hates Rocketeer hes jealous dark has a twisted soul now. He could be that kind of character.

II. I think to ad some detail to the universe a few guest appearances from celebritys of the day. like John Wayne, Humphrey Bogart, Vincent price.

III. I also think the first wave universe gave DC a chance to create new original characters based on the 30s 40s 50s that would never fit in the original continuity. Like the rocketeer for example.

IV. This idea could possibly push it to far but idk maybe not. Possibly revision some modern heroes in a 40's style.

The crimson avenger.@Grandsteam: I don't think solomon Grundy can be in this universe because super powered characters don't exist in it.

@crimsoncake: yea I guess you have me there. I wasn't thinking about that to much. his main power is undying. I still think he would be good in that universe but you are right on that one.