Check out frog fractions!

Crumble A speedrunning platforming game, where you play as a blob with a tongue. Pleasant experience to play through while learning, while absolutely balls to the walls insane when actually speedrunning, actually 100% achieved this

Cyberpulse Twin-stick arcade neo style virus slamming game. Great control precision, challenging and colourful. The right thumbstick pressing might take a bit of getting used to.

Pseudoregalia Such a fun old school platformer. Big bunny girl MC for some reason but SUPER FUN and satisfying movement mechanics and the world is built well enough for the mechanics. A few hour long game, unless you look everything up.

Actually going to put some indie demos here I played this weekend, that I really enjoyed: Half-Sword Physics based medieval combat game. Reminds me of Exanima but instead of 2.5D, you can play Half-sword in 3rd or 1st person, which is really fun. Can have full gore or turn the gore completely off.

Tainted Grail: The Fall of Avalon First person (potentially later also 3rd person) RPG, very much in the vein of Elder Scrolls or Dark Messiah of Might & Magic. Really enjoyed the demo, it takes place on the tutorial island/dungeon. Going to buy the full version when it releases, because there seems to be a save wipe for 1.0.

Bloodthief Reminds me of Neon White and Ultrakill having an even more indie baby. Seemed to be pretty simple and good speedrunning platforming fun.

Shape of Dreams 2.5D action RPG roguelike. Very pretty and gameplay feels good. Didn't play it quite enough yet, only thing I kinda disliked was the amount of cooldowns on abilities.

9Kings Small town defense game with waves of enemies led by other kings attacking your kingdom. Really enjoyed this one. Demo isn't too difficult, even when I am really bad with these type of games.

RKGK (RAKUGAKI) 3rd person platforming game, where you bring some colour to the world with your graffiti. Very fun movement and popping colours. The dialogue isn't necessarily for me but the gameplay felt really fun.

Unbeatable Colourful rhythm adventure game, style is great and soundtrack slaps.

Check out Tunic. I would recommend going blind.

Top of my list right now is Vintage Story! It's like a serious version of Minecraft, with more focus on realism.

Cult of the Lamb.

Monster sanctuary (turn based monster collector) and Roboquest (arena shooter) were a couple from recent years that stood out to me

For older games nethack and dwarf fortress are great if you can look past the graphics

Most of what I play is indie and choosing a favorite is too hard, so instead I'll go with biggest playtime. Antimatter Dimensions, also on Steam, has quickly shot to having the highest playtime of my Steam library. It is an idle/incremental game. Bonus points: free! Most of the idle/!incremental_games@incremental.social I have played have been free in the browser without IAPs, and seem to have been made by one or a few people.

Not counting that, I'd probably have to go with Stardew Valley.

Probably gotta be Starsector

The video that hooked me

Brotato

Exanima Unique physics-based isometric dungeon crawler also featuring an arena career mode.
Moddable.
Really slow development cycle, though.

Severed Steel Futuristic 3D shooter with maybe the best movement system I've tried, with wall running, full 360 air movement, sliding and more.
Weapons have only one magazine, so you're constantly sourcing them from your enemies while blasting holes into the fully destructible levels.
Very replayable.

For me it's Rimworld

I guess either Shovel Knight or Hades

ya know what, I'mma round it out as a Top 5, so let's throw in Bastion, Bloodstained, and Dust: An Elysian Tail as well.

Live for Speed

I've been playing it on and off for over 20 years now with some definite highs and lows but I have nothing but respect for the devs (3 people) and community. It's not on any store fronts and they just do their own thing.

LINK

Dave the diver! /s

But seriously I'm a real sucker for platformers, and so A Hat In Time is my most favorited one. It brought back this sort of charm I haven't felt since the n64 days and I love it!

Stray and Kena: Bridge of Spirits are pretty awesome too, would be my second and third favorites

One of my all time favorites right now is Brok The Investigator.

It's a game by French company COWCAT Games that is describes as a point and click beat'em-up game. Has lots to do because there are multiple endings. It has a free visual novel made to essentially showcase a vn engine that can be used to make BTI fan games or your own creations and has an upcoming DLC (apparently only gonna be $9.99) that focuses more on the combat side of the game.

It's currently available on PS4/5 (vita planned but scrapped), xbox (don't know if they mean one and series x/s or just series), switch, steam, itch(dot)io, and even epic if you hate yourself.

Sayonara Wild Hearts is a magical experience that can't be described honestly. On difficult stages, it engages all your senses and you're just 100% inside, enthralled by the visuals, music and rhythm. This is probably the most focused and most precise game ever, everything it has, works. It's not just my favorite indie game, it's one of my favorite games ever.

Also, Night in the Woods and Keep Driving. Both resonated with me emotionally in a lot of ways, touching the things I care about. Keep Driving also has a really fun gameplay loop and an incredible music selection (which works as a boost for that emotional factor).

Honorable mentions: What Remains of Edith Finch (it made me uncomfortable and scared at some moments) and Firewatch (nice way to tell a story, and the characters feel real).

super meat boy

Crosscode for sure! They have a new game in the works as well, it looks like it will be just as good. Great time to get into it

Another Crab’s Treasure.

Oh, haha, a souls game but with crabs, funny parody haha!

Except, no, while it does seem like it would be compared to SpongeBob humor, and it does self censor “shit” to “ship”, the themes of the story go well beyond just “Crab must find his stolen shell!”

It takes time to ramp up but in some ways it feels like a better-written game than most Soulslikes (to me, that’s not a high bar given the way many of them wrap their lore in many layers of obfuscation that you don’t get to enjoy in the moment)

Watching speedruns and trying NG+ is also a lot of fun.

i'm not sure The Ur-Quan Masters counts as indie

Dungeons of Dredmor! Just a really solid, straightforward roguelike with a ton of stuff and a cheeky sense of humour.

Banished, you can't get more Indie than just one guy's passion project.

I don't know what it is about that game but it really struck a chord with me and I've come back to it over and over. It's my favorite game to play when I'm sick and can't do anything. It's relaxing and peaceful and cozy while also being complex and ruthlessly challenging at the same time, so it's like spinning plates. Seems easy when you get the hang of it but it can all come crashing down if you make a bad enough mistake. It's spawned some copy cats, and I've tried them, but the original just gets me somehow.

The Binding of Isaac is already a famous title that has influenced so much of the roguelike/twin-stick-shooter genre. This game has permanently altered my taste in video games.

The game I’ve enjoyed as much as TBoI is Tiny Rogues. It’s much smaller, but still fantastic with rich build variety while never losing the need for skill and good reactions.

Stolen Realm is a turn-based tactical RPG that takes place in procedurally generated dungeons that play like little roguelike runs with overarching character progression. It’s multiplayer, but you can also just control up to six characters on your own too. It does eventually feel pretty repetitive and there are points that seem impossible to win, but it’s a unique game where you continually build that roguelike power fantasy and just progressively become more powerful to the point of it feeling game breaking.

Going Under is an adorable roguelite where you fight through various levels themed around a blend of corporate stereotypes and fantasy creatures like a crypto company run by skeletons or a delivery company run by goblins. The combat is a vaguely souls-like with an emphasis on weight and timing, but your weapons are office items found in each room that break down very quickly.

Webbed is a cute puzzle/platformer where you play as a little spider on a quest to save your spider boyfriend. The main gimmick is that you can shoot webs to create platforms, pull things, attach things to each other and more. It’s a short and sweet game that’s still decently challenging. It’s the only non-roguelike indie I recommend and it’s that good that I love it despite it being in a genre I rarely play and almost never finish.

Used to play battlefield 2, BC2 and 3 alot. Then I stopped playing online games and recently started playing "Ravenfield". It's succesfully filling the void, there are even battlefield maps and some vehicle/heli/jet/tank mods and ignoring the fact that it looks like battlefield heroes (very indie-style graphics), the physics/handling feels pretty close, especially when flying heli and shooting rockets

Tactical Breach Wizards

The vast majority of my favourite games have been listed, many multiple times, so I'm gonna go with some I didn't see, though I didn't look exhaustively, here we go:

Horace

Quite a hidden gem in my opinion, almost no one I mention it to has heard of it. 2D platformer with an amazing story and some interesting gimmicks. One of the most surprising and unforgettable indie games I've played.

The Messenger

Ninja action-platformer that is way more than it first appears if you stick with it. Hilarious writing, great controls, and amazing music. Genuinely one of my favourite games.

Yoku's Island Express

Almost entirely unique in it's idea. It's a pinball-metroidvania where you're a postman dung beetle, and it really works. Gorgeous world, super chill vibes, clever puzzles... What metroid prime pinball should have been.

Pyre is my all time favorite, it's the only game i've ever platinumed and still kept playing to see a few more permutations. But by terms of sheer hours put in? Rimworld.

Swapper

Not my actual favorite, but it's very high on my list, and I didn't see it posted yet.

Most of my picks have been mentioned already, but I had a blast with Mullet Madjack. A tongue in cheek riff on 80s anime in a boomer shooter where you have 10 seconds to live, but each enemy kill gives you 2 more seconds of life.

I haven’t seen it mentioned and feel like it should count, since it really just had a solo programmer working with a graphic designer and musician, but RollerCoaster Tycoon and RollerCoaster Tycoon 2 took a big chunk of my gaming time.

Minimetro and Cultist Simulator are my go to "comfy" games, but cultist simulator really does get you feeling like you're chasing a mad eldritch horror when playing at times. It's deliberately obtuse and odd, and then a revelation of the truth takes you over and you push on beyond your wildest expectations.

Slay the Spire and Hollowknight have both been mentioned enough in other posts in case anyone reading this is somehow unaware of either of them.

Faster than Light and Into the Breach are both excellent games. FtL is rng mitigation and crisis control par excellence. ItB is basically chess, and you play out the turns as best you can. It's rewarding, but once you get good you need to ramp up the difficulty somewhat to keep it fun.

I really like Isle Wars and Scorched Earth

I have a personal soft spot for Doki Doki Literature Club because it got me into programming when i was young, but that's far more sentimental and to be honest i wouldn't play it again as an adult really. If i had to pick something functionally though I'd say Project Zomboid. there's a fuck ton of fun to be made in that, especially with Multiplayer. Even in singleplayer i like to turn on a NPC mod and assemble my own makeshift Walking Dead cast

I'll have to go with Selaco, it's not even finished (in fact it's approximately half done) but it feels more complete than any mainline Halo game after H:Reach. Looks better too.