Never really agreed with the Metroidvania label, same with Skul: The Hero Slayer. You unlock different biomes (and side rooms), but the items to do so are more like keys. Just my thoughts on that.
Absolute favorite is probably either Bloodstained or Castlevania Portrait of Ruin. Every Metroid and Castlevania is good though. Ender Lilies, Shantae, Momodora and Alwa are some other ones I've really liked off the top of my head.
Not Hollow Knight, which thinks it's clever to not fill out the map as you go unless you happen to pick the path the map dude is on. Makes me feel like my time isn't respected which is a pet peeve of mine. Also other than bosses the combat is boring and repetitive and you don't get stronger fast enough for revisiting areas to not be a slog.
I mostly play on PC these days but historically it was Nintendo consoles. I like exploring maps.
Good picks, but I don't think Dark Souls qualifies as a metroidvania. Metroidvanias gate off parts of the map based on what abilities the player has/doesn't have, whereas Dark Souls blocks off parts of the map simply because you're missing a key. Also, Dark Souls doesn't really have ability power-ups with the exception of acquiring the Lordvessel.
I have to recommend Ascent DX - it is free, quite short, but it condenses everything I enjoy about the metroidvania genre I to a bite sized play session.
Tunic is one of the best games ever made, nevermind just in the metroidvania genre. It is good for reasons I can't tell you without spoiling some of the magic. Trust me!
Phoenotopia Awakening was stupendous fun and way bigger than I thought it would be. Strongly recommended. Typical side scrolling platforming gameplay, with emphasis on exploration and puzzles as well as the combat and platforming.
Death's Door was so damn fun, and it felt quite fresh in a way I can't describe. Its an isometric hack n slash game with some puzzle elements. Tells a cool story, and is a sequel/successor to Titan Souls, from the same devs.
AAAAXY was a lot of fun, and free and open source. Sort of like antichamber meets metroidvania. Short and sweet but also challenging!
Otherwise, as others mentioned, I can't recommend these enough!:
I see most of my faves have already been covered by others, so I'm going to add the Metroid Prime games. Unlike the mainline Metroid games, which are awesome in their own right, the Metroid Prime games are played from a first person perspective.
You still get to explore, you still get power-ups, but because you can scan almost anything with Samus' visor, there's some actual worldbuilding, which the mainline Metroid games didn't really start doing until Metroid Fusion (which was alright, but Metroid Dread did a better job at worldbuilding, I feel). As for the platform, I played the GameCube versions on the Wii.
I like the feeling of getting stronger and coming back to previously inaccessible places. Pretty much only play games on Steam.
I'm surprised I haven't seen anyone mention Hollow Knight yet. I won't claim it on my list since I haven't finished it yet, but it seems to be popular.
I'll throw in a few that I enjoyed (all pc with a controller):
Hollow knight (probably the common favorite). Fun gameplay, interesting story, felt like a great entry into the genre as someone who didn't like them previously.
Bloodstained: Ritual of the Night. Really interesting farming mechanics to unlock new skills and fun combat. I think I liked this one mostly for the gameplay and don't remember the story much.
Grime. This one felt really, really clunky at first. However, like most games in the genre, it really picked up at one point and I enjoyed the whole experience. I think there were some sections that really dragged on but overall a fun game with interesting movement, mechanics, and enemies.
Hmm… metroidvanias never really stick the landing for me, but I had fun playing through SotN back in the day, and I'll shout out a couple of modern ones with fun combat: F.I.S.T: Forged in Shadow Torch and Prince of Persia: The Lost Crown.
I'm going to throw a shout out to Environmental Station Alpha because I think it's an excellent game that flew under the radar of a lot of people when it launched. It makes some bold decisions with the story that some people might not enjoy but the gameplay is solid and the backtracking problem (which most metroidvanias have) is solved by having the level get harder as you progress.
It's cheap, it's not at all hardware demanding and it's very heavily inspired by Metroid. If you enjoy metroidvanias and you haven't played Environmental Station Alpha you definitely should.
And a secret shoutout to Noita. The dev of Environmental Station Alpha worked on Noita. It's been pushed into the roguelite category but I would argue it's the worlds first open world(s) roguelite metroidvania. If that sounds stupid but interesting, prepare to suffer because Noita is not at all easy and that's deliberate because the central theme of Noita is the pursuit of knowledge (the more you know about Noita the easier it gets).
A lot of good recommendations in here, some I've played, some I'm adding to my list!
I'll share one that I haven't seen in the thread yet: Crypt Custodian. You play as a ghost cat sentenced to clean garbage in the afterlife. Good mix of exploration and combat. I personally hate when combat keeps me from progressing in a story, so I like that they have Easy/Normal/Hard modes but that you can also further customize assists, like adding up to 3 extra hit points. You can also buy a market to show you the next place to go when you're feeling stuck. Very good cozy-gamer territory.
The story wasn't overly complex, but very sweet–the ending made me cry. I loved elements of the story like one of the bosses being the personification of grief.
I played it on XBox Game Pass, but it was worth paying for.
Ori and the will of the wisps (don't love blind forest personally)
Blasphemous 1 and 2
Pretty much all the 2d metroids, especially Dread
Guacamelee 1 and 2
The messenger kinda
Steamworld dig 2
Animal Well
Oh and what I like about them. Exploration is 90% of a good metroidvania for me. Unlocking abilities and finding secrets in old locations is just my favorite gameplay loop. I don't tend to love super linear metroidvanias a-la Metroid fusion, though it's still a good game. But exploration usually can't be all of it. Combat if it's there should be decent at best, puzzles are always good. But really if exploration isn't there just right I probably won't love it. Also most of these I play on steam deck / PC. Except metroid