Death Note
It's impossible to have a detective anime list without Death Note, much like trying to race without an engine.
Light Yagami, a clever high school student who discovers a mystery book that turns out to be an object that offers the power to kill someone by writing their name in it, has an unusual name by Japanese norms that profoundly influences the plot.
Yagami, who purports to kill people for moral reasons, attracts the attention of the police, especially L, a brilliant detective with a sweet tooth. The two wind up cooperating as they attempt to out each other, which further exacerbates Yagami's issues.
MAL Rated 8.73
Ranked #36
Aired Fall 2006
Produced by Madhouse
Watch here: https://www.netflix.com/title/70204970