If you're looking for anime similar to Welcome to the NHK!, you might like these titles.
Shiki ends up keeping a black cat while Mikiya Kokutou is out of town. Meanwhile, Ririsu Miyasuki, a student of Reien Girls’ Academy, suffers from the loss of her best friend who committed suicide by jumping off the Fujou Building. When she tries to kill herself, she encounters her classmate Asagami Fujino, who has psychokinetic power.
After transferring into a new school, a deaf girl, Shouko Nishimiya, is bullied by the popular Shouya Ishida. As Shouya continues to bully Shouko, the class turns its back on him. Shouko transfers and Shouya grows up as an outcast. Alone and depressed, the regretful Shouya finds Shouko to make amends.
Narumi Fujishima is an ordinary high school boy who is isolated from his classmates. When he reluctantly joins the gardening club and meets the reclusive, genius detective named Alice and her band of detectives known as the NEETs, Alice hires Narumi as an assistant and puts him to work solving the strange mysteries of Angel Fix, an illegal drug that makes people go crazy. Little does he know it could put him and Ayaka in serious trouble.