Planetarian - Really sad, especially if you like robots. It'll absolutely bum you out, especially if you only watch the 5 episode series. I recommend the movie "Hoshi no Hito" (aka "Stargazer" aka "Storyteller of the Stars"), since it's most of the series plus new content. "A Snow Globe" also recently came out, so that's another thing you can watch if you liked it. I recommend queuing up some moeshit slice of life to watch afterwards, because it'll probably make you a little depressed.
https://myanimelist.net/anime/33190/Planetarian__Hoshi_no_Hito(Manga note: There is no manga, it's adapted from a completely linear/non-interactive VN)
Shiki - A little drawn out but it's cool how it plays with morals, there's not really a good side or a bad side, it's just two sides trying to survive in spite of each other. I just love how it takes the concept of the vampire and makes it realistic instead of just emo superman like a lot of fiction does to vampires. It mostly reminds me of "Let Me In"/"Let The Right One In" if you've seen either of those films. Also to note that two episodes got cut from the TV airing for being too gruesome (If you download it, check if it comes with episodes 20.5 and 21.5, those are the unaired episodes. 20.5 was genuinely hard for me to watch).
https://myanimelist.net/anime/7724/Shiki(Manga note: The anime is great but if you really, really liked it than I recommend the manga since a couple things are different, it's not like JoJo where it's a 1:1 translation)
Gankutsuou - Gay Count of Monte Cristo. It's The Count of Monte Cristo so it's automatically good. I really like how they retold the story to be from Albert's perspective, honestly it almost feels like the original story should have been written this way. I once heard that you can turn a story from a heroic quest to a Greek tragedy just by changing the character perspective and this is a great example of that.
https://myanimelist.net/anime/239/Gankutsuou(Manga note: The manga was made after the anime, and it looks like dogshit. I didn't read it but if you like manga that much then knock yourself out)
