After the AKB48 Group, which J-pop groups have the most members ?

Well AKB48 for sure also it's Nogizaka46 joining this list along with them same as all their sister groups

the numbers fluctuate, but there are several mega groups in japan that could hold the title

the girl groups i know are

akb8, ske48, nmb48, hkt48, ngt48, stu48, nogizaka46, sakurazaka46, Hinatazaka46

a boy group

exile tribe, but i don't think they technically count.

and finally though they're on hiatus there's a co·ed group called Yoshimotozaka46

EXILE TRIBE is the largest boygroup with 52 member (58 if you count former members and the one who had passed away)