Grab a big box of tissues and watch Grave of Fireflies. Hard pressed to name a piece of cinema that's made me a bigger anti-war guy.

For lighter stuff - Full Metal Alchemist (I'm partial to Brotherhood over the original, but they're both good). Avatar: the Last Airbender is Amerime and a bit young, but a genuinely great story. I've got a special place in my heart for "Scraped Princess" and "Escaflowne" as well.

Two of my favorite new anime, Delicious in Dungeon and Frieren, also great stuff. They're just not finished yet, so you can't binge them.

taking you literally and i'm going to go by decade here. only 2 per decade, which is gonna kill me for some of the later ones, but otherwise i'd be here all day

1970s

• mobile suit gundam: the 1979 anime that started it all, this is the best place to start for one of the biggest franchises in anime. fascinating to see where basically every scifi trope in anime comes from. but it's also just an incredibly well told war story on its own, no broader context necessary. the way the mystery of char expands and gets revealed is incredible, amuro's trauma is explored in some interesting depths, the whole cast is really strong. and it's got classic scifi psychedelia in ways that make it obvious that it was coming off the tail end of 60s counterculture but in a really unique way that manages to feel super profound
• rose of versailles: oscar dejarjayes is the (fictional) captain of the royal guard in late 18th century france, serving under marie antoinette. a woman raised as a man so she could be her father's heir, she's basically the best at everything but is kinda dumb. courtly drama! exploration of gender in some kinda problematic but still very interesting ways that are very progressive for the 70s! and then the back half depicts france just falling apart in the leadup to the french revolution as the nobility completely fail the people. unrest builds, things get worse, and the french revolution happens

1980s

• armored trooper votoms: in the grim dark future of the whatever millennium this takes place in there is only war. chirico cuvie is an ex-soldier who just wants to figure out why his unit betrayed him, and is forced to live through the plot of every single action movie made in the 80s. he suffers through a cyberpunk megacity full of corrupt cops, underground mech fight rings, mad max style biker gangs, multiple prison breaks, and an evil priest. and that's only in the first arc! later he fights in the vietnam war, gets trapped on an abandoned spaceship where all his sins are laid bare in front of him, wander the wastelands of a desert planet while being chased by someone after revenge, and ultimately collapse a massive galaxy spanning conspiracy. fantastic stuff, and the mechs in it are some of the coolest of all time. make sure you watch the sequel ovas because they rule.
• dallos: what if the battle of algiers happened in space? on the moon? and had mech fights? and was the first ever ova and was just absolutely gorgeous classic 80s animation? just really good stuff, the generational differences within the colony are fascinating

1990s

• revolutionary girl utena: utena tenjou has a dream. she's going to become a prince on a white horse, just like the one who saved her when she was young. no hyperbole, the greatest show of all time. a surreal exploration of gender roles, funny animal antics, memory, sexuality, and the tyranny of the automobile. but most of all it's about abuse, systems of power, and how to break free. if you watch one show i recommend please make it this one, i cannot say enough good things about it. infinitely gayer than you'd expect from a show that aired in the same timeslot as season 1 of pokemon. content warnings for a LOT of shit, lmk if you need anything specific
• turn a gundam: if you only watch one gundam it should be this one, it's the best that gundam gets. after 2000 years, the people of the moon come down to resettle an alternate earth that's basically pre world war one europe. the closest i think a tv show could come to matching (and honestly sometimes surpassing!) the pastoral kinda steampunk aesthetic pioneered by hayao miyazaki. incredibly gentle and brutally horrifying in equal measure, with all the damage you might imagine caused by asymmetrical mech warfare. also the protag has Gender in a way that's remarkably well handled considering it was 1999. here's a scene from the first episode that gives me goosebumps from how beautiful it is

2000s

• hellsing ultimate: if you like schlocky b-movies you'll love this. hyperviolent in a way nothing else on this list is. vampires led by van helsing's granddaughter and her servant alucard vs catholic supersoldiers vs nazis (most of the nazis are also vampires). imagine the coolest shit you can imagine vampires doing with the biggest guns you've ever seen (like, dual wielding anti-tank rifles is the START) and imagine it's all presented with massive amounts of style. content warning for sexual assault, both threatened and enacted
• death note: kinda edgy incredibly dumb homoerotic mind games, just a lot of deeply ridiculous fun. light and L going back and forth while L's theme plays is peak. nothing comes close. simply the best to ever do it at the things it's trying to do

2010s

• revue starlight: the weirdest audition for a high school theater program i've ever seen. 7 girls are competing for the lead role, but this manifests as them having beautifully animated sword fights under the supervision of a giraffe. each girl gets her time in the spotlight where her own specific past and reasons for wanting the role are explored. all of them get real homoerotic with it. fascinating show with a lot of stuff to say about the nature of art and passion. the movie is even better than the show, so make sure you check that out after
• nichijou: absolutely wild comedy that tries every style in the book, cannot recommend it enough. words can't really describe what makes the high school antics so good, but it's willing to throw everything at the wall and every joke lands. it can have surreal pythonesque humor about strange societies that live on blimps right next to a very grounded comedy bit about 2 girls chatting and fucking with each other and they both work so well. i watched an episode at a time with friends over the course of months in between other stuff as a little treat and loved it

2020s

so i actually haven't watched that much anime i love this decade, but there's been some good ones

• bocchi the rock: kinda comparable to nichijou in some of the humor styles, but this has a much more structured story about an incredibly anxious high school girl joining a band and making friends. very pleasant, with some hysterical ways of portraying her fears and a super strong cast including the VERY attractive alcoholic bassist mentor. also has some incredible scenes when they're performing, making you really believe this high school band has what it takes to maybe make this a full time thing one day. i'm rooting for them, and i'm rooting for bocchi to get a girlfriend! (it's very funny that the series has a few lines that make it clear she's gay but it never comes up on account of the crippling anxiety and resulting lack of any relationships or even crushes)
• keep your hands off eizouken: incredibly creative show about a crew of autistic teenagers who want to make anime. the 3 have to figure out all the different things it takes on their own, without letting their imaginations run wild and outstrip what 2.5 animators can do in a relatively short period of time. just a fantastic show, with one of the most energetic and fun opening credit sequences of all time

mob psycho 100 is a delight.

Have you seen Ping Pong the Animation?

Samurai Champloo, Gintama, Odd Taxi, Made in Abyss, Ouran High School Host Club, Soul Eater, Assassination Classroom, Chainsaw Man, Puella Magi Madoka Magica, Baki, Cromartie High School, Azumanga Daioh, um...that's all I can think of without googling

Notable ones from recent years:

• Birdie Wing - Lesbian golf anime. A European girl competes in unsanctioned underground golf tournaments to keep her family afloat, falls into love/rivalry with Japanese (underground unsanctioned) golf prodigy. Don't worry if you have no interest in golf whatsoever, this anime makes golf look like an actually interesting sport

• Mob Psycho 100 - Wholesome, wacky, subversive. A shy, physically unfit, unpopular at school just so happens to be born with psychic powers greater than any other living human. However, the focus is the journey he has in improving himself physically, becoming more socially outgoing, and emotionally stable. He genuinely wants to live life where he succeeds or fails based on his effort rather than using powers given to him at birth. 3 seasons, fully contained story.

Sazae-san is still going from 1969 to today.

Legend of galactic heroes

Galaxy express 999

Gundam the original one.

check out future boy conan for a classic miyazaki adventure series. late 70s, incredible animation, kinda establishes a lot of the standard miyazaki tropes in a post-apocalyptic agrarian vs doom tech world. available on yewchube last i checked

Evangelion (followed by End of Evangelion), Madoka (followed by Madoka: Rebellion), One Punch Man, Mob Psycho 100, Redline, Cyberpunk: Edgerunners, Kaguya-sama: Love is War, Monthly Girls' Nozaki-kun.

Oh shit, everything but Evangelion is after 2010, uhhhhhhhhhh Legend of the Galactic Heroes! There, now I've got 3 decades covered.

Watch The Rose of Versailles. It's very good. Manga was made in the early 70's, anime 79-80.

MegaloBox is an under rated personal favorite of mine. It is a bit overlooked but it is supposed to be a spiritual successor to ashita no Joe. Only it kidna has cowboy bebop type vibes. There is a seccond season. They both have strong leftist themes which is kinda out of nowhere for the modern anime industry.

busy rn, will respond later

Legend of galactic heroes. Think game of thrones done right (but in space)

Some gems that haven't been mentioned yet:

00s-early10s (some personal favs from a LOT of anime I watched in this decade - geass, death note, etc all classics but well known and regarded).

School Rumble: Yes it's highschool romcom, but perhaps the peak of the genre. Also a very early role for one of the greats, Ami Koshimizu as Tenma

Sayonara Zetsubou Sensei: The anti-high School romcom. I've always personally felt it was basically taking the piss out of shit like Negima and all the characters are fucked up. If you like Bakemonogatari you gotta go back and experience the original SHAFT kino.

Hidamari Sketch: the other SHAFT classic. This + SZS = Madoka. It's ume-sensei's work and the adaptation is very peak Shinbou style. As with most anime, there's gonna be some fan service but I've always felt in terms of "cute girls doing cute thing" shows this was the most earnest, since it really also tackles what it means to be creative (they're art students)

Kara no Kyoukai: technically movies but the best Nasuverse stuff and the only one I'd ever unequivocally recommend. Some great ufotable animation as well.

Eureka 7: surfing Mecha! Great music! A slow burn that you might not be able to get through the annoying protagonist for the first 30 episodes

Black Lagoon: doing crimes in the Pacific. It's very cool and explicitly anti Nazi.

80s/90s

Gunbuster: my eternal recommend, though caveat- it's Gainax with OVA fan service (nudity). Still one of the few truly great anime endings, it's something else when you finally get to the final scene of episode 6. You will feel feelings.

G Gundam: you probably caught some of this on toonami, but it still rocks pretty damn hard as a hot blooded mecha show

Initial D: EUROBEAT

Wow I didn't think I'd get such an active post! Thanks to all the comrades who have contributed, and will continue to contribute. Lots of great suggestions in here! Going to bookmark this thread and then possibly compile it into a organized list when I have time.

I'm a big fan of Satoshi Kon's stuff - You'll already be somewhat familiar, since Paranoia Agent had a good run on [AS]. Check out Perfect Blue and Tokyo Godfathers.

On that note, anyone around here think Gunsmith Cats is worth a go? I was thinking about checking that one out. Apparently it's really Chicago-heavy.

Paranoia Agent just cause I don't see it listed here yet.

Ninja Scroll (the movie is much better than series imo).

Steins;Gate

It's always at the top of all time lists and revolves around time travel and is my personal favorite

Ranma 1/2

It's about a Karate guy who turns into a girl, but really just the vibes of the age it was made in are magical

Series

FLCL is a goofy off-center coming-of-age sci-fi.

Excel Saga is a parody anime that shoots at nearly everything pre-2000.

Hellsing Ultimate is a vampire action that is a faithful recreation of the manga, both in style, action, and the goofy self-aware parts.

Tengen Toppa Gurren Lagann is what Gainax put out after they decided they went too far with Evangelion, and that the world needed a full-throttle Mecha series.

Kill la Kill is from a studio (Trigger) formed by everybody who worked on Tengen Toppa Gurren Lagann.

Mahou Shoujo Madoka Magica (and the movie, Rebellion) is to magical girl anime what Evangelion was to super robot anime. Would you like to form a contract?

Code Geass: Lelouch of the Rebellion because you must pleasure yourself with this fish and maybe find out where all the memes come from.

Elfen Lied is a credited influence for the series Stranger Things, particularly El(even)

Escaflowne is a mecha in a more steampunk world. It's also the only series I know that uses Tarot as a plot device.

Bakemonogatari is a high-school romance comedy with some of the funniest and clever wiring. Sorry, writing. I stuttered, Ararararararararararagi.

Movies

Redline is a sci-fi racing movie that reminds me of SW E1 Pod Racing.

Summer Wars is a cozy Miyazaki-adjacent romance with some sci-fi flairs.

Interstella5555: The 5tory of The 5ecret 5tar 5ystem Before Daft Punk did their Tron-inspired music video movie, there was another album-length movie made from their Discovery album.

Vampire Hunter D is a vampire hunter movie set in the very far future, giving it a western feel.

1917 - Nakamura Gatana. The very first anime: an entertaining short about an incompetent samurai.

1970 - Ashita no Joe. Excellent boxing drama with class conscious elements (despite being written by a conservative). Has a sequel from 1980.

1971 - Lupin III. Wacky hijinks of a thief and his crew, spawning a franchise lasting to this day and extremely popular in countries like Italy. The first eight episodes are significantly darker in tone, until Miyazaki (yes, that one) took over as director due to poor ratings. The 1977 version is the one most people remember, but part 1 is excellent too.

1973 - [NSFW] Belladonna of Sadness. Feminist arthouse movie about witchcraft, sexuality and revolution.

1978 - Future Boy Conan. Miyazaki's last full length TV anime, featuring many of his usual themes.

1979 - Mobile Suit Gundam. "Real" Mecha political drama that spawned not only a very popular series, but a whole genre. Has sequels in 1985, 1986 and a movie in 1988.

1979 - Rose of Versailles. Shojo drama about the period leading up to the French revolution, and an excellent portrayal of the societal changes that led there.

1981 - Chie the Brat. Very underrated and fun movie by a future co-founder of Studio Ghibli, featuring only local Kansai area voice actors.

1981 - Fang of the Sun Dougram. One of the peaks of real Mecha storytelling: the story of a guerrilla civil war, with a corresponding focus on politics.

1983 - Armored Trooper VOTOMS. Same director as above. Less of a political story and more of an atmospheric sci-fi mystery with a killing machine MC.

1983 - Cat's Eye. Knockoff Lupin III, but with art thieves. Surprisingly good and not too horny compared to the author's next work.

1984 - Urusei Yatsura 2: Beautiful Dreamer. One of Mamoru Oshii's best movies. It doesn't require knowledge of the setting.

1985 - Dirty Pair. Fun sci-fi/action comedy with surprisingly good writing and lots of western media influences.

1986 - Dragon Ball. Once you get past the most problematic part of the show, it's actually a fun show justifying the spawning of a shounen behemoth.

1986 - Maison Ikkoku. Slow burn romance story/slice of life show with some pretty bad filler, but the payoff is worth it.

1987 - Bubblegum Crisis. 7/10 sci-fi show with a 10/10 soundtrack.

1987 - [CW] City Hunter. The most 80s show around, an action/comedy with gorgeous art. The main character is unfortunately a huge creep.

1988 - Mobile Police Patlabor. A cop Mecha show made by a bunch of leftists? Why yes. The 1989 TV Version, it's 1991 OVA sequel and the first two movies are also excellent.

1988 - Armor Hunter Mellowlink. Revenge story in the VOTOMS universe.

1989 - Mobile Suit Gundam: War in the Pocket. Gundam at its most anti-war.

1992 - Sailor Moon. It's fun.

1993 - Irresponsible Captain Tylor. Half parody, half serious space opera, with some pro-anarchist themes and a kickass soundtrack.

1993 - Slam Dunk. Hilarious basketball Shounen worth watching even if you don't like the sport.

1994 - Mobile Fighter G Gundam. Gundam at it's most awesome/bombastic.

1995 - Tenchi Universe. Early harem show, but with a lot of heart missing from the rest of the genre. Less horny than the OVA.

1995 - Slayers. Konosuba, but better and not Isekai. Lina Inverse my beloved.

1995 - Neon Genesis Evangelion. Of course.

There's more , but I'll leave it at that for now.

Hajime no Ippo (english name: Fighting Spirit) is probably my favorite anime of all time. It's about a kid who becomes a pro boxer, and while it is a pretty stereotypical sports show, every single element of the show is absolutely top quality. The manga is still ongoing (I think?) but there's no filler because whenever they caught up to it they stopped producing episodes and waited however many years it took for a couple more story arcs to build up - which means that the anime was released in 2000, 2009 and 2013, meaning it actually spans over a decade.

Azumanga Daioh is on youtube in its entirety and might be my favorite anime. Watch it.

Akiba Maid War is a fun "what if the Yakuza was made up of maid cafes?" show

If you like ecchi stuff Ganbare Douki-Chan is a very cute romance anime about office workers, all free on youtube, only about 45 minutes in total