Nanatsu no Taizai, Enen no Shouboutai Recommendations
The main male protagonists of both series are strong and quite intelligent without being OP or oversmart. Both have horrible reputations and their pasts influence the respective plots greatly. Strong bonds between comrades are shown in a quite casual manner and it doesn't become melodramatic or forced. The fights are quite well written and don't have illogical power-ups just so that the good guys can win.