bandwagon jumping:-
Jath's Juveniles
Durgo's Delinquents
The Doomed Patrol
The United Planets Youth Organised Under Regimental Systems
Legion of Super Youths
Young Legion
The Legion Youth (starched jodhpurs for all)
Gen-Next
The Sol Defenders/ Metropolis Defenders
Legion Boot Camp
The Delinquents
The Boarders
The Young Warriors (see recent Superboy thread)
The Peacekeepers/ New Peacekeepers (see recent Superboy thread)
Cadets has some Legion background - From Who's Who in the Legion