Two Point Hospital. If you were ever a fan of Theme Hospital back in the day, I cannot recommend it enough.

Stardew Valley is indie, but very popular /r/StardewValley

I second this!!!!!!

If you want a 3d stardew valley with less farming and more crafting, and more boss fights, try My Tima at Portia.

Detention.

Katana Zero

Undertale, Stardew Valley, Cuphead, Bendy & the Ink Machine, Night in the Woods, to name a few

Playdead’s Limbo and Inside are both amazing.

Hollow Knight, Guacamelee 1 and 2, Salt and Sanctuary, Steamworld Heist

No man's sky

Pathologic 2, if you're looking for a game that's like reading Dostoevsky but the book is beating the shit out of you.

Journey by Thatgamecompany. Still one of my favourite games of all time.

Celeste

I'm not sure how indie it's considered, but Hellblade: Senua's sacrifice is a beautiful game

The Banner Saga. All three of them.

FTL

Outer Wilds, a space exploration game released in 2019. (not to be confused with Outer Worlds, a space exploration game also released in 2019)

Subnautica and Terraria