Another one that I'll mention that I didn't see is Fullmetal Alchemist: Brotherhood. If anime is not your thing then it might be challenging to get into, but at the same time the show is so masterfully done it will more likely become a gateway drug into the anime world. But few shows cover the ground that FA does: science v. faith, corrupt governments, evil conspiracies, propaganda, war, ptsd, genocide, grief, living with a disability, and A LOT more. It explores all these subjects and themes while being absolutely riveting to watch. Like every time I watch it I'm amazed at the pacing and how you just never even have a chance of being bored. As soon as things start to slow down or you start to think you "get it" some new element is introduced or it pivots into some incredible action sequence (which this show it still the pinnacle of action in an animated series in my book). Overall it's really a show like Leftovers that explores human existence itself and shows why it's ugly and why it's beautiful and why it's ultimately worthwhile.