Indie games have really delivered in quality the past 10-15 years. With that said, what are some of your favorites?

Mine include the below (in no particular order besides the last one being my favorite)

Hollow Knight - With a blend of Metroidvania and Soulslike elements, Hollow Knight wasn't groundbreaking but it stands tall amongst the best indie games as well as MetroidVania games in general. Challenging at times but always felt like jumping right back into the action.

The Witness - Simple concept of drawing lines on a grid but so satisfying and challenging at the same time.

Lost Winds - It's a game about wind, specifically, harnessing the power of the wind with your Wii remote which made for an enjoyable adventure. One of the first WiiWare games I owned and thoroughly enjoyed due to its use of the WiiMote and had a beautiful visual style.

Braid - Played a huge role in the rebirth of the indie game scene and is an undoubtedly well crafted game. Hand drawn visuals, soulful violin music and an interesting central time control mechanic, made Braid a well realized and enjoyable experience.

Bastion - Supergiant Games made their debut into the indie scene with this action, narrative-driven adventure game. Its soundtrack, voice acting and unique world made it shine quickly and kept me engaged throughout. 

What Remains of Edith Finch - What Remains of Edith Finch was utterly distinct. Great narrative which dealt with tragedy. I'll leave it at that as to not spoil anything.

Hades - Quite possibly the best recent indie game. Hades is a one of a kind rogue-lite game that blends a few different genres. It has  satisfying and fluid action and modifiers that build replayability. 

World of Goo - My favorite indie game of all time. It was breathtakingly fresh, deep, gorgeous and inventive. It's packed full of brilliant, challenging levels. It's gorgeous. It's got beautiful music and atmosphere. And it controls really well. An experience that I will never forget.

Indie games on my to play list:

Ori Series

Cup Head

Gone Home

Disco Elysium

Plague: A tale of Innocence

I'm kind of iffy on the definition of "indie" to be honest; does Hellblade qualify? If so, that.

Most games labelled as indie aren't my thing as I find they don't meet the bar for production value that I expect of a game on modern hardware.

I haven't played Cuphead as I don't like extremely difficult games but I did play and like Ori and I am interested in Subnautica, yes.

I believe the most common definition thrown out there for indie is a game made by a small developer or team.

Not sure Ninja Theory would qualify for that.

So does Ori qualify, considering it's published by Xbox Game Studios? Cos that would probably be next in line if Hellblade doesn't count.

Also liked The Swapper, World of Goo, and The Vanishing of Ethan Carter, but as I say indie games generally aren't my thing, I find most of them to feel too cheap.

My list

1. Cavernous wastes, one man project for PSVR, can't get more indie
2. Pixeljunk Shooter 1,2
3. Journey
4. Pixeljunk Eden
5. Fez
6. The Way
7. Pixeljunk Sidescroller
8. Pixeljunk Nom Nom Galaxy
9. Flower
10. Braid

Other favorites
Machinarium, Creaks, Closure, Papa & Yo, The unfinished Swan, Space Invaders Infinity Gene, Infinifactory, The Talos Pinciple

Axiom Verge deserves a special mention. It's got a great story with some clever methods of surpassing some possible issues of ludonarrative dissonance. It also has very inventive Metroidvania upgrades, which is pretty rare in a genre that likes to just repeat Metroid upgrades all the time. Not the best combat unfortunately and I think some of the game to game stuff can be a bit dry, but given it's only around 8 hours I don't think it's too big of an issue at all. I'm actually just as excited for Axiom Verge 2 as Hollow Knight Silksong, because I really think Axiom Verge is surprisingly inventive in such a saturated genre.

Shovel Knight (Wii U/Switch)
Pullblox World (Wii U)
Mighty Switch Force 2 (Wii U)
Affordable Space Adventures (Wii U)
The Swapper (Wii U)
FAST RMX (Switch)
Hollow Knight (Switch)
Cuphead (Switch)
Thumper (Switch)
Horace (Switch)
Super Hexagon (PC, Android)
Paper's, Please (PC)
Undertale (PC, PS4, Switch)
Blasphemous (PC)
LIMBO (PC)
INSIDE (PC)
The Stanley Parable (PC)

I might be forgetting some...

EDIT: Oh, Axiom Verge (Switch)

My favorites would include a lot of games already listed: Hollow Knight, Celeste, The Messenger, Shovel Knight, Blasphemous, but I'd like to spotlight two since nobody's mentioned them.
Helltaker - it's a bit short, feeling much more like a demo than a full game, even if you go back and unlock everything. But it's free and fun for the short time it lasts. The narrative is simple in premise, but hilarious in execution.
Stealth Inc 2: A Game of Clones - If I had to slot it into one genre I suppose it's Metroidvania with the consistent upgrades/gadgets and interconnected world you explore, but rather than combat the focus is on stealth/platforming. It's a very fun game with a Portal-esqe plot and antagonist.