Does it have something to do with loss or death?
Aquaman - baby died, Aquaman died
Elongated Man - wife died, Elongated man died
Kilowog - planet died, he died
Martian Manhunter - planet died, team members died
Powergirl - planet/universe died, mother and father died
Superman - planet died, he died
Tomorrow Woman - died saving JLA
Vixen - team members died
Wonder Woman - Amazons disappeared, she died
Zatanna - search for lost father, Zatara dead now?
Jim Johnson - still living