It depends on your tastes, if you want something darker go for chainsaw man, hunter x hunter or berserk (really dark but if you can stomach the sick parts is one of the best manga of all time) more light hearted go for my hero academia(gets darker later on) or one punch man. There are a bunch more like good night punpun, vagabound, monster... and i would also recommend the stuff written by Carnby KIM. He is a manhwa(korean manga) writter, and although manhwa are usually really bad, his work is consistently great even by manga standards.