This news is slightly old, but it is believed that we now know the full launch roster. 22 of the initial 24 characters have been confirmed.
12 heroes:
Aquaman, Batman, Cyborg, Flash, Green Arrow, Green Lantern, Hawkgirl, Nightwing, Raven, Shazam, Superman, Wonder Woman
10 villians:
Bane, Black Adam, Catwoman, Deathstroke, Doomsday, Harley Quinn, The Joker, Lex Luthor, Sinestro, Solomon Grundy
In addition to them, the last two villians have been leaked. Wonder Woman villian Ares has been leaked
here and
here.
Killer Frost has also been leaked by the following images.