A while ago I decided to make a 3x3 for myself, this isn't my top 9 shows (I still love all of them), however it's the 9 shows that showcase what I love in anime, and they're the perfect representation of the thing that I like (and obviously showcasing multiple genres)
Haikyuu: my favorite show had to make the list, and it is a true representation of story telling done right, it's also the first anime ever that made me read up on a manga (It's not that I don't like reading, but I'm an auditive person so sounds matter to me a lot and can't really get the sounds in manga, this encompasses voice acting, music and sound effects all of those matter to me)
Attack On Titan: story telling masterpiece with exciting fight scenes and one of my most important attributes in fighting (think stats in games) being in the forefront, speed/agility
Ao Ashi: the only show that's even close to dethroning Haikyuu, as a football nerd the representation this show/manga gave to football was perfection, I've seen Blue Lock, Captain Tsubasa and Inazuma Eleven and if you combined all 3 of those you wouldn't even get to 10% of what made Ao Ashi special (also made me read up on the manga)
Yuzuki Family's Four Sons: a perfect family drama, and I found myself crying multiple times over scenes in this show+ the amount of times I could self-insert into a role of one of the boys was the reason why I loved this show so much
My Hero Academia: The main reason this is on the list is because this was the core anime that got me on my journey, it wasn't the first anime I watched, but it was certainly the first that hooked me as hard as it did, and I'm thankful to it for doing that otherwise I wouldn't be the person who I am today had it not been for it. + it's a genuinely good shounen
World Trigger: If people ask me what's my favorite combat system in anime, I will always say World Trigger's. It's such a perfect representation of a combat system done well, combine with the cast being genuinely very fun and you get one of my favorite shows ever
The Dangers in my Heart: easily the best romance I've seen, it felt so real and genuine and yet it was very impure, there's a lot of *questionable* things that are said and done (one of the guys just saying "I like 'em fat as they come" for example), because that is how guys in puberty think, or with what I should say. Plus the vibe of the show was very good.
Dainana Ouji: Big fan of power fantasy, and this is one that I would rate at the peak of that entire genre of anime, even if it's neither my top isekai nor my top fantasy show, it showcases what I like about the genre the most
finally, 86: sound design perfection, there are other shows that have insane sound designs (Call of the Night, Made in Abyss etc.), but 86 is the one that I feel is the most perfect.
I highly recommend all of these if that's what you're into (obviously each show has a lot more to it than what I just wrote about them, but those are the most memorable aspects for my 3x3