Death Note is considered one of the best anime of all time but the second story Arc is rushed in the anime as compared to manga the side characters got more screen time in manga.
Image Credit:- IMDB
Horimiya
This anime follows the story of two classmates who fall for each other. This anime has 16 volumes and the anime adaptation feels rushed compared to the manga.
Image Credit:- IMDB
Gurren Lagann
Gurren Lagann is one of the most popular Mecha anime of all time but the anime adaptation feels rushed. Especially after the time jump the pacing of anime feels fast.
Image Credit:- IMDB
Monthly Girls' Nozaki-Kun
This is a romance comedy anime with a good story too but for some reason, the second season of this anime didn't come even though the manga has enough material.
Image Credit:- IMDB
Hunter x Hunter
Hunter X Hunter is another popular anime series that ended too soon. But it is not limited to anime the manga isn't making any progress either. They're both stuck and no one knows when we will see next season.
Image Credit:- IMDB
Bleach
Bleach anime is also one of the most popular anime of all time but in 2012 this anime ended even after having enough manga material. Until the next season of bleach returns after a decade-long wait.
Image Credit:- IMDB
No game no Life
No Game No Life is another popular Isekai comedy anime which is really popular but the second season of No Game No Life isn't coming out at all.
Image Credit:- IMDB
Grand Blue
Grand Blue is another popular anime with High school drama and comedy. This anime also has enough source material to have a second season but the chance of getting a second season is slim.