So many solid suggestions here already. I have a soft spot for the more retro styled games, and despite being short Gato Roboto is one of my favourites. It just feels so good to play.

Super Metroid will always be my favourite. I also enjoyed Axiom Verge and Bloodstained ROTN.

I generally like shorter Metroidvania like Iconoclasts and some of the Shantae series or even Yoku's Island Express which has some backtracking.

The Metroidvania tag is a bit like Dubstep in music, a lot of those Dubstep tracks aren't Dubstep but they can still be fun for some people.

Ghost Song is one of my favorites that doesn't look like its been mentioned yet.

Guacomelee should get more love, it's a really stylish game and there is even coop if you want to play together with someone.

People calling search action games metroidvania is a big pet peeve of mine. No idea why it bothers me. Anyways hollow knight is my favorite, followed closely by silksong.

La mulana 1 and 2, animal well for puzzles.

Metroid dread, highly recommend for combat.

Dead cells and rouge legacy two for rouge lite bits

terraria for minecraft + metroidvania

time spinner, bloodsworn for more typical metroidvania

the old castlevania games are on steam, so there is that

almost metroidvania suggestion is Outer wilds. Progression based learning. just not in a 2d plane and no fighting.

Just so it's not forgotten to time I want to recommend AM2R (Another Metroid 2 Remake). It's basically what if Metroid 2 was made in the Super Metroid engine.

I'd recommend any of the 2D Metroids, but if you're going to play Metroid 2, that's the version to play.

I don't know if it's "favorite", but an old classic was Aquaria. It had a surprising amount of content, even to the point of several secret bosses, and an absolutely excellent soundtrack. Sadly, the main guy behind it is dead now. Ori was also fantastic.

Castlevania: Aria of Sorrow

Aria of Sorrow

I was shocked to see no mention of Ori in any of the comments here before I realized you had already recommended it in the OP. I have no issues with seconding that, the Ori series is really good.

I love this style of game. I always have one on the go. Some times they scratch the itch, others they miss just a bit. I found that the blasphemous series more dark souls than Metroidvania. Biogun, chasm, bloodstained, any of the ori games, haiku, the mummy demastered, turnip boy commits tax evasion, dust an Elysian tale... I have more but that's a solid chunk. I'd love to hear from others if they do or don't consider these in the same family.

Do you consider Zelda64 a MetroidVania? If so then Darksiders has that action, similarly control, soul reaver 1 and 2, and blood omen 2.

Headlander was surprisingly fun. Probably not my favorite, but certainly up there.

New school: Hollow Knight and Silksong

Old school: Super Metroid

Animal Well is stellar

I also really liked Ender Lilies/Magnolias.

Other metroidvanias I've really enjoyed that haven't been mentioned yet are Blasphemous and Vision Soft Reset.

Blasphemous has a really cool theme and is pretty challenging.

Vision Soft Reset is more indie and probably PC only. It has a unique twist to the formula.

A few other good ones that come to mind:

Axiom Verge

Bloodstained: Ritual of the Night

Guacamelee

Momodora: Reverie Under the Moonlight

Rabi-Ribi

A Robot Named Fight (it's basically if super metroid was a roguelike)

Touhou Luna Nights

Cave Story

Also, the Castlevania Advance Collection is three GBA metroidvanias, definitely worth getting if you wanna play/replay any of those.

i can tell you the one that surprised me the most: Yoku's Island Express! utterly adorable pinball metroidvania. you're a little dung beetle pushing a big ball around to deliver mail.

i find that there is so much focus on dark and dreary in the metroidvania genre, which makes sense considering the roots of the genre. me, i get enough of that in my daily life. i want colorful and full of curiosity. the ori games are good for that too, as is supraland, but i don't know of many more.

I haven't played very many, and these might not be pure Metroidvanias, but I recommend:

The Messenger

Pseudoregalia

Tunic

Surprised it hasn’t been mentioned yet but Aeterna Noctis is one of my favorites and I have played a LOT of metroidvanias. Some of the platforming sections are quite difficult but there is an easier mode with easier enemies and platforming. It has a huge map and some really cool mechanics I haven’t seen before.

Edit: a couple more I thought of that aren’t listed. HAAK is a fun one, another one with some interesting mechanics and a fun story too. Souldiers is more of a 2d RPG game but it still has some Metroid mechanics. Four classes you can play as with a good story.

Castlevania: Symphony of the Night. The game so good it created the term “Metroidvania” even though the formula was basically “Metroid”.

I haven't seen Shadow Complex on here yet.

It's an older title (2009) and even the remastered version is from 2016.

Still one of my favorite Metroidvania type games.

https://store.steampowered.com/app/385560/Shadow_Complex_Remastered/

Rogue Legacy 2, if it counts. Otherwise, Axiom Verge.

Record of Lodoss War: Deedlit in Wonder Labyrinth is a fantastic experience.

Played a lot of these in the last two years, with Ender Magnolia and Nine Sols being my favorites among them.

All-time I think I'd still go with Super Metroid, despite its age and having completed multiple playthroughs I still end up playing for hours anytime I boot it.

Honorable mentions for Rabi-Ribi (don't let the cutesy anime artstyle fool you, this is a fantastic non-linear game with some of the best boss battles in the genre), the recent Momodora games and the Team Ladybug games (with Touhou Luna Nights being my favorite of the three).