Should probably be more specific about that:
* If you like adventure-game style puzzles, La Mulana and its sequel.

I'm with the "Hollow Knight best metroidvania" train here.
I've said it before but the game took a long time to click with me, really long time. Looking back, the desolate world and lack of stuff to do, other than exploring was probably the main issue for my lack of interest but once more mechanics are introduced the game is pure satisfying awsomeness.
Some people don't like the checkpoint type save mechanic but for me wan't a issue other than freaking Traitor Lord wich was not only the hardest boss for me, the last checkpoint is kinda far away with some platforming in between. I've died there many, many times.

I'm eager to play Silksong.

Edit:
Ori and the Blind Forest is also a very nice game, more focused on precision platforming rather than combat.

For some reason, I find Bloodstained dull as heck. the colorfull 3D graphics are awfull but have some nice effects later on. While I enjoyed Castlevania SOTN and find it engaging, Bloodstained is kinda meh, not sure why.

The lack of colorblind mode is indeed a issue in Guacamelee and while I bought the sequel long ago, I still didn't play it. I will have a look. Was not a breaking issue for me though, since the game don't punish for deaths, other than trying again. Finished the game just fine and for the most part, the game is actually easy.

Maybe me but I can't imagine playing any of the mentioned games without a gamepad.

For me, it's not the checkpoint saves that bother me (though the Traitor Lord case is a problem), but rather the fact that the game auto-saves without the player's consent. I don't like it when the game forces me to take a death penalty with no option to instead reload from the last save, or when the game doesn't let me do some experimenting and then reload to before the experimenting was done. (For example, I wish the game would let me buy a charm, play around with it to see if I like it, and then reload from before I bought it.)

I had a look (~10 minutes since the game was stuttering for some reason) on the second game and from what I could tell is pretty much the same as the first (played super turbo), some colors seem a bit different but the issue is still there.

I'ts been a while since I played anything except Godhome fights but I seem to recall the game doesn't auto save except when you sit on benches.
While not straight foward, using a second save slot may solve the issue for you, or in a more extreme case a backup of the save file. (something my pride won't let me do, ever. I never savescum, I promise)

It auto-saves when you die, as well.

I think it may auto-save when you pass through certain (temporary) points of new return, like when you first enter that rainy city.

Also, you can't switch charms without using a bench, which in turn triggers a save.

Bloodstained: Ritual of the Night
+1

Psychonauts.

The answer is always Psychonauts

Because I didn't get into the topic before you did :p

I was fortunate enough to win Powerslave: Exhumed in one of doc's generous giveaways here on this forum. It is one of the best games I have played in a long time. I play on Pharaoh difficulty, and finally getting through Set's Palace for the first time was a satisfying moment. The game has been described as a predecessor of Nintendo's Metroid Prime, too.

As for another game not mentioned, Dead Cells:
https://www.gog.com/en/game/dead_cells

I don't have beyond the first couple DLCs and haven't played the game since the 1.0 version, but I loved my experience there too. I suppose, though, that it may not be considered a true Metroidvania...not sure.

Absolutely get Hollow Knight if you haven't yet.
I can also recommend Apotheon and Valdis Story: Abyssal City.

I will always support recommendations for Psychonauts.

Hello nick187!

Let me throw in some suggestions that are less mentioned.

Regarding Metroidvania-type of games, I found some NES-inspired games fulfilling that itch very well:

Odallus the Dark Call (A fantastic Castlevania-inspired dark fantasy Metroidvania with lots atmosphere.)

Alwa's Awakening (part 1, 8-bit NES-style)
Alwa's Awakening The 8-Bit Edition (dlc, NES rom needs an emulator)
Alwa's Legacy (part 2, 16-bit SNES-style)

A remake of an old Sega console Wonder Boy game with on the fly switchable graphics and sound that combines action platforming with light Metroidvania elements and hidden secrets searching. While the later game "Monster Boy And the Cursed Kingdom" is more of a Metroidvania-style game, I prefer the smoother handmade sprite animation in "Dragon's Trap" and its 80s level design:
Wonder Boy - The Dragon's Trap

An old favourite of mine is VVVVVV (The Letter V Six Times), neither exactly a Metroidvania nor a platformer per definition, but it has a semi-open level/world structure and instead of jumping using a gravitation flip mechanic in an adorable C64-/Atari-inspired aesthetic:
VVVVVV

Another favourite of mine is "Lumo". An homage to the old ZxSpectrum (pseudo) isometric platform adventure games with modern (infinite lives) gameplay mode and less obtruse puzzles. The first half are linear levels. In the latter half you have a small hub and branching, looping paths similar to Metroidvania games.
Lumo

And if you are looking for a gimmick-focused challenge packed with a very specific kind of humor, then I can recommend you the following platform games (that can be frustratingly hard at times):

88 Heroes (Just read the game page description--a crazy idea of a game.)

Jump King (See the full game title on the game page--worms/artillery-like jumping mechanic with focus on verticality.)

Bread and Fred (Similar to "Jump King" with a caveat--you are tied together with a second player or a rock. Has a lot more horizontal space than "Jump King". Timing- and coordination-based in two player mode, while more puzzle platforming in single player.)

Have fun!

Kind regards,
foxgog

Minor accessibility issue for Dragon's Trap: If you're playing with retro graphics, then whenever a boss takes damage, the screen will flash red, which could be a problem for some players. If it is a problem for you, you should switch to modern graphics whenever you're fighting a boss. With modern graphics, this isn't an issue. (Note that switching is as easy as pressing a single button; hence why this potential issue is minor.)


Another game I'd recommend for those who like the Igavanias: Timespinner

Think Castlevania (like the Metroidvanias), add in time travel between two different eras, then throw in a bunch of queer NPCs, and you get Timespinner. It's a rather fun game, aside from the guide-dang-it moment that requires checking a skeleton.

It does have the problem of becoming too easy as the game progresses, as enemy damage fails to outpace your increasing defense.