Romantic Killer
A comedy/romance with surprisingly dark themes (read: I'm pretty sure it's also psychological horror). A magical being tries to make the protagonist (Anzu) fall in love but Anzu resists. A lot.
Anzu is a wonderful character, both on a comedic and serious level. The "love interests" are great too.
Warnings: attempted rape (I meant what I said, it gets DARK), stalking, trauma, bad parenting (bordering abusive or neglectful), blood, slavery
Madoka Magica
Magical girls making wishes and fighting witches but dark and mysterious. Somewhat well-known in the magical girl genre, for good reason. It's very well-crafted - you can see the world's rules and characters' actions and goals influencing the story episodes before they're said out loud.
Warnings: murder, despair, self-harm
Revisions
Sci-fi war between mechas and monsters (AKA the two things that look good in Netflix's 3D animation) with time travel, which is quite unique and deep, but still makes perfect sense.
The main cast is great, everyone has a unique personality and reactions to events and revelations.
Apparently a lot of people find the protagonist annoying (he is proven right after people hated him for a decade and has a big superiority complex for most of the series) but his character arc of getting humbled is done very well.
Warnings: murder, existential dread
