[Starseeker]

Hey Soda! I used to read mangas/watch anime in junior high, so a couple years ago Right now I don't have any 'contact' with manga/anime except for playing Genshin Impact.
Anyways, my favourite mangas were Death Note, Tokyo Ghoul and Magi (although the Magi anime is much better than the manga imo). I enjoyed Ao no Exorcist and Akame ga Kill!, too.
If you're curious what they're about:
Death Note (contemporary) - I'd say it's the darkest among the ones I mentioned, you're probably familiar with the name;
Tokyo Ghoul (contemporary with fantasy elements) & Akame (fantasy) are quite brutal, there are graphic depictions of violence, so if you don't like it I don't recommend them. They have interesting storylines, though;
Magi - set in a kinda '1001 Nights' world, it's all rather pretty and friendly, but with a very good plot;
Ao No Exorcist (contemporary schoolkids, with fantasy elements) - there are exorcists and demons, but I wouldn't call it brutal.