Not including movies, I have currently seen roughly 27 different anime, and not necessarily all the seasons of some of those anime (ex. Haven't seen Spy x Family season 2/3, haven't seen past season 1 of Attack on Titan and One Punch Man).
Here are my top 10 favorites from what I have seen.
Note: Interesting distinction which many people I think don't realize is an important distinction: It's a list of my favorite anime and not a list of what I think are the best anime. Since it's my favorite, I can just use random perhaps unjustified opinions I have to judge things. When discussing best, I think that's a more objective question rather than subjective. Anyway, here are my picks:
Starting from the bottom and going to #1, we're beginning with an honorable mention: The Promised Neverland. I loved loved the first season; it was fan-freaking-tastic. Big problem, though: The 2nd season was absolutely terrible 🙃 Like actually terrible. So here it sits in HM land.
HM: Erased
I think Erased is quite good -- I think the concept is fascinating, and overall it is really well done. The ending was a bit rushed, and the spoilers got spoiled to me (regardless, are allegedly fairly easy to figure out), so that's not good either. Regardless, I still think it's a great anime. It was in my top 10 when I first drafted this post, but then I watched Frieren: Beyond Journey's End and it shifted Erased into HM land.
10. Hunter x Hunter
Hunter x Hunter is fantastic. It's pretty much what I wanted to get out of long-running anime. It not being complete yet is bothersome to me, but if I remember correctly, the current ending is satisfying enough. Due to it's 148 episode length, I don't see myself rewatching it unless they release new stuff, but it was a ton of fun, the characters are great, some of the arcs are just so good. Great stuff.
9. Haikyuu!!
So I just rewatched/caught up with Haikyuu! It was great. Can't say I absolutely loved it though. There were many parts that were absolutely phenomenal. A ton of fantastic character moments and character arcs. The fact that they were able to build up and have a phenomenal moment about being a pinch server is just fantastic.
But, also, like: The anime is too long for what it does? And too unrealistic? And has random subplot strings that go nowhere/feel unnecessary/I don't enjoy?
Idk, maybe those things only bug me, but for some reason the errors in this show seemed more prevalent/noticeable compared to errors in other shows.
I've cooled quite a bit on Mob Psycho. In the past, I would consistently say it was in my top 3 favorite animes. Now, let me say: It is REALLY good. I think what's really holding me back from ranking it higher is the third season. The third season just wasn't my favorite :/ Which is an absolute shame.
The first two seasons are some of my favorite stuff, but I'm ranking the show as a whole, so the third season drags it down a few spots for me. If I ignored the 3rd season, I think this would most likely be top 3 or 4. And perhaps I'm over hating on the 3rd season; it wasn't bad per se, just not very good, imo. Idk.
7. Frienen: Beyond Journey's End
This is my most recent new anime I've seen and it is simply wonderful/incredible/amazing. I've fallen in love with the world and the characters, and everything is extremely well done. It could very easily climb the ranks of this list in the future. Thinking about it, frankly, it should probably be higher. Currently just waiting on more episodes to eventually release. In its current state, it feels like just the beginning, which makes it a little more awkward to rank super highly, imo. But I am very excited for more, and, like I said, I think once more does come out it could easily go up.
3, 4, 5, 6, and 7 were all very tough to rank. I love My Hero Academia a lot, and feel it could easily take any of the 3-7 slots. I gave Fullmetal Alchemist: Brotherhood the edge because the ending is so good in Brotherhood, and My Hero isn't done yet. Having good endings is important to me (similar issue with Frienen and Hunter x Hunter right now). I really hope it ends satisfactory.
Another reason I lowkey feel it's not higher is its high episode count which continues to grow. As kind of referenced, this is a downside to Hunter x Hunter as well. But its peaks are impeccable, and it's just a show I enjoy. It's just fun; a comfort anime in a way.
5. Fullmetal Alchemist: Brotherhood
Wonderful wonderful show. I've also seen the original, but I rewatched Brotherhood recently, and I'm fairly confident I prefer Brotherhood, so I'm only ranking it. This show is, like, actually so good. Characters are incredible, fights are superb, world is fascinating, storyline is awesome. So good. Love and agree with the fact that it's generally regarded as one of the best animes of all time.
4. Steins;Gate
There's a thrill in the back of my mind when thinking about this anime. It is so tense, so interesting, so cool. So so good. Does time travel extremely well, imo. Goated anime.
So Your Lie in April has been my favorite anime ever since I originally watched it, but I rewatched it this year and decided it no longer was. Major plotline I just didn't like this time around is the main thing. Do I absolutely adore it still? Of course. Incredibly emotional; I cried this watch through for sure for sure.
It would not surprise me if it slips a couple-few spots more, but for now its legacy of it being my absolute favorite for years is keeping it in the top 3. My heart is still full of love when I think of this show, and that love is simply stronger than other shows right now. But for the first time in a long while, it is not my number 1.
2. Odd Taxi
Holy, I love this anime. The characters are endlessly fascinating and fun. The storyline wraps up so incredibly. It's mix of serious and light-hearted moments is wonderful. Absolute banger. Thanks for the recommendation old roommate Joe.
Let me tell you, this anime is a masterpiece. I'm not sure if there's a single thing I would change about it. It is beautiful and wonderful and poignant and I wrote all whole blog post about it a while back which you can read here. I did not know it would become my favorite anime back when I wrote that, but after rewatching it again recently with my roommates, I was reminded of how much I adore this perfect little anime.