The Legionnaires: The Substitute Commandos
Chlorophyll Kid, aka Ral Benem of Mardru, aka Plant Lad. Created by Edmond Hamilton and John Forte.
Color Kid, aka Ulu Vakk of Lupra, aka Color Queen. Created by Edmond Hamilton, Curt Swan, and Jeff Greenberg.
Fire Lad, aka Staq Mavlen of Shwar. Created by Edmond Hamilton and John Forte.
Keith Giffen has admitted that he's put the Substitute Heroes through some ups and downs. Up until the (second) Levitz era, they were straightforward second-stringers, nothing more. Then the famous issue of DC Comics Presents that featured Superman and the Subs versus Ambush Bug turned the Subs into a joke team: enthusiastic but underpowered and not quite competent. This image of them persisted and largely remains today (see also the portrayal of the Subs in the animated series and the upcoming take on them in the pages of Straczynski's The Brave and the Bold. Geoff Johns's use of them in his Legion arc in Action Comics is not the same thing; Johns found a handle on the Subs that was both respectful and amusing, and I hope Paul Levitz picks up on it), despite Giffen's subsequent rehabilitation of the characters.
In the Five Years Later era, Earth has been secretly taken over by the Dominion, and a resistance movement has formed to fight them. The core of this movement is the Legion of Substitute Heroes. As the stakes rise in this struggle, a commando team raids one of the Dominion's underground facilities, and three longtime Substitute Heroes get to show us what they're made of.
(These three heroes, like most of the other Subs, were Legionnaires during the Five Year Gap, and their tenure with the Legion has been essentially unrecorded. In the retroboot Legion, Fire Lad and Chlorophyll Kid are still hanging in there with the Subs, but Color Kid was blinded by Earth-Man's "Justice League".)