Most definitely Flamebird.
flamebird.jpg
Nut also adding to the chorus for Empress
Argent
Kole
Kid Devil
Nightshade
Fury (Lyta Trevor)
Speaking of The Outlaws, I believe another obscure character could make for a wonderful new member...
Walter West: Dark Flash
Speaking of The SuperFriends, I'd be interested in the return of...
The Junior Super-Foes
Young injustice. The general, match, inertia, silver swanii, white lightning, little Circe
The junior Super foes, (in BOTH incarnations) are just regular teens who got recruited by villains to be cannon fodder lackeys. Version 1 was sidekicks of Cheetah(Priscilla Rich), the Human flying Fish(I have no idea who he is either), Penguin, Toyman, and Posion Ivy(back when Ivy used gadgets to manipulate plants). So they're teens with no actual powers training to become sidekicks of villains who mostly use martial arts skills and gadgets to fight.
The new version makes them all Batman villain wannabes and not actual sidekicks. Still has Penguin and Poison Ivy, but replaces Cheetah with Catwoman(still has Kitten who looks the same though), and the Toyman and Flying fish with TWO Joker wannabes. Then they go and fight the robins... who beat them way too easily TBH... given that this version uses some sort of nanotech derived from Batman computer data to make them able to fight like the criminals they want to imitate.