Best extremely Underrated anime of all time?

Yo! I’m looking to cover some anime that are GROSSLY UNDERRATED on my YT channel and would love some suggestions!

For me I’m thinking in the vain of BoBoBo, Barakamon, Monthly Girls! Things that are truly so good, but sadly never got the recognition they deserved.

Also a lil note as to why you think they’re underrated would be lovely.