Kaiju No. 8 is one of the best anime to watch after Demon Slayer. It follows the story of the Kaiju defence force which protects the whole world from giant monsters with superpowers who are trying to destroy cities and people.
Tokyo Ghoul
If you love watching dark and violent anime then this one is for you. The story follows a war between ghouls and humans it becomes more and more dark after every episode. It has 4 season and every season is great.
Dororo
Dororo's story takes place in old Japan. Where a selfish lord sacrifices his child to save his kingdom. But the child was alive and finding a way to recover his body. The story has so much to over demons, politics and action.
Soul Eater
Soul Eater is one of the best and most underrated anime of all time. The anime is really good but a lot of people don't even know about it. The story is set in a high school and weapon meisters and a human weapons.
Bleach
If you don't know about Bleach then you have no idea what are you missing. There are so many modern anime inspired by bleach. The story revolves around a soul reaper who protects the world from Hollows.
Attack On Titan
The whole of humanity is trapped inside giant walls and the unknown monster called Titans constantly trying to destroy those walls and enter them. Our protagonist lost his mom and decided to kill every titan.
Goblin Slayer
Another underrated anime on this list. Goblin Slayer follow the story of an adventure who only slays goblins. The story is dark and filled with violence a lot of don't know about this anime but you should watch it once.