Sprout/Tefe Holland https://dc.fandom.com/wiki/Tef%C3%A9...nd_(New_Earth)
Ultra the Multi-Alien https://dc.fandom.com/wiki/Ace_Arn_(New_Earth)
Zook https://dc.fandom.com/wiki/Zook_(New_Earth)
Manitou Raven
the League of the Ancients
Always loved the Obsidian Age story line and subsequent JL:Elite book.
Corona https://dc.fandom.com/wiki/Kako_(New_Earth)
Dark-Crow https://dc.fandom.com/wiki/Daniel_Cr...ss_(New_Earth)
Yankee Doodle Dandy https://dc.fandom.com/wiki/John_Dandy_(New_Earth)
Has Glorith been seen lately? She started as a Silver Age lackey of the Time-Trapper and was deaged into protoplasmic slime in her first appearance, but somehow recovered from that and continued to torment the Legion of Superheroes.
Willpower. The son of Johnny Thunder. The only JSA kid no JSA ongoing has used yet.
Argus — the Bloodlines character. Always worked well with Flash. And his identity as undercover law enforcement lends itself to storylines.