12 titles recommended if you like Tegami Bachi: Letter Bee
The Seven Deadly Sins: Four Knights of the Apocalypse
Dorohedoro
The Case Study of Vanitas
Dead Mount Death Play
Harem in the Labyrinth of Another World
Seraph of the End
Bye Bye, Earth
The Faraway Paladin
JoJo's Bizarre Adventure
Mushi-Shi
D.Gray-man
Tengoku Daimakyo