The Justice League of America was created in 1960 to be DC's flagship superhero team, and combined seven of the publisher's most popular and most powerful heroes. They helped create the Silver Age's fixation on team comics, with the likes of Avengers, X-Men and Doom Patrol following soon after. The Justice League have seen many heroes join the team over the decades, but some felt more out of place than others.
Source：https://www.cbr.com/justice-league-weird-rosters-ranked/
