I think top 5 NPO is Deadshot, Darkseid, Batman, Superman, Catwoman.
Red Hood, Scarecrow, Starfire(probably), Green Arrow are right up there too.
Black Adam, Canary, Fate, Atrocitus, Supergirl, Harley, and Green Lantern kick ass too.
Flash, Firestorm, Blue Beetle, Cheetah, and Bane RIGHT behind those characters
Robin, Aquaman, Cold, Brainic, Cyborg, Ivy are pretty good too
Only real outliers on the low side to me are Joker, Swamp Thing, Grodd, and maybe Sub. Sub is fuckin weird, idk. I don't think he's really all that good but he has uses.