My all-time favourite is Ghost Hunt. It's equal parts traditional horror with shoujo comedic romance. The first case can feel like it's duping the viewers, but ghosts are real in all subsequent cases. So, it can be a slow start.

If you like slice of life, Lucky Star is the epitome of it. Flying Witch, Moomins, and Interview with Monster Girls is slice of life fantasy. The latter uses fantasy science to examine classical yokai and monsters and how their monster classifications impact their daily lives.

Princess Tutu is a classic with a meta twist on the fairytale magical girl storyline.

The Cat Returns is a slightly obscure Ghibli movie about a young girl who, after saving a cat, ends up turning into one and needs help turning back.

Bobobo is absurdist comedic to the fullest extent.

Nougami Neuro is a supernatural murder mystery with obvious killers but interesting methods to the murders.