Sproggiwood

Rouge like turn based dungeon crawler. Certainly not new by any means, but still a pretty decent little dungeon crawler. The art is cute and the game is pretty simple to pick up, which makes it perfect for more casual play. That said if you're a completionist, it can get a bit repetitive, but nothing too hair-pulling. Probably not worth the full sticker price, but historic sales have knocked it down to $1.49, which is a nice balance between cheap and fun (took me about 28 hours to 100%).

13 Sentinels: Aegis Rim

Sadly, it's not available on PC, but it is available on Nintendo Switch (US eShop page linked above) and PlayStation 4 (and PlayStation 5 through backwards compatibility).

It's a sci-fi game made by the creators of some games you might've heard of in passing (namely Dragon's Crown, Odin Sphere, Muramasa: The Demon Blade, etc.), Vanillaware. I can't go into any details about the game itself because of spoilers, but I will say it is quite simply the best and most uniquely told story I have ever seen in a game. It's a game you have to experience for yourself. You should go into it as blind as possible, too.

I will say the English dub of the game is also surprisingly good, considering it was recorded almost entirely in COVID lockdown. The Atlus West sound engineers (Atlus published the game in the west) must've worked some incredible magic to get it to sound as good as it does.

Concord is a...nah, I'm just kidding. I've never played it, and I don't intend to. It has fewer than 1000 reviews though.

We Who Are About To Die

https://store.steampowered.com/app/973230/We_Who_Are_About_To_Die/

Physics based Gladiator roguelike. Work your way up, start fighting with boards dressed in rags in city crossroads for the amusement of peasants, and end a God of Blood fighting in gold in the Coliseum!

Or die along the way. You'll die a lot along the way :)

Megabyte Punch is a side scrolling fighting game where you build your robot with different parts salvaged from fought robots that give you different abilities and powerups.

It is a super fast, casual game that you can bang out in a few nights. It has a pretty good electronic soundtrack, boss fights feel weighty even if they are relatively simple.

One of my favorite games as far as just fun and de-stressing!

Within a Deep Forest

The first game I ever completed and the first time I left a review for a game. The music, the atmosphere, the design, everything blew away. It was freeware from back in 2006. Made by a guy called Nifflas. It's a sidescrolling platformer where you are an intelligent bouncing ball. I still think about it to this day.

Chained Together

Multiplayer platforming game where you're chained to up to three other people trying to escape Hell by climbing up, up, up. I've only played it 2 player, which was fun, and can only imagine how chaotic 4 player would be. Can be played solo, but I wouldn't recommend it.

EDIT: For once, I'm glad to see downvotes! Good to know it's gotten recognition.

Mobmania https://store.steampowered.com/app/2099220/Mobmania/

It's an Bullet Heaven game like Vampire Survivor. You can play online with up to 4 Friends and every Character has it's own Skills. The Game is still in Early Access but it gets Updates regularly.

One Way Heroics+

Semi-Rogue-like RPG, flee away from the darkness on the leftside of the screen, try and defeat demonlord and save the world. (Multiple endings)

One of my favorite games ever, guy made his own engine.

It does have design flaws, don't get me wrong. But this is is really novel and has enough content to get somewhat deep into it.

Eventually you start seeing the same things but for essentially a one man team it's really impressive.

To me, Ctrl Alt Ego is not well known enough. It is an immersive sim in the style of Prey. You play as a robot roaming a station, where your Ego (like a spirit) can pass into and control all sorts of objects to solve puzzles, evade, control or kill enemies. The graphics aren't impressive (it was made by a 2-person team) but the gameplay is so interesting and the story is surprisingly compelling and funny!

Evoland 2

Evoland 2 is an unique RPG, with its graphic style and gameplay changing as you progress through a deep storyline based on time travel.

Minishoot Adventures is a twin stick shooter with a 2D Zelda-style map.

VoxeLibre, what started out as a Minecraft clone is now trying to go it's own way. Does what it says on the tin. Being not quite MC gives it something fresh, yet familiar imo.

For my it's Bone's Café.

Imagine overcooked but where you kill and use your customers as ingredients and can raise skeletons from the dead to automate as your chefs and servers. It's overall a very well put together game, especially for one with 240 reviews (total)

https://store.steampowered.com/app/1739070/Bones_Cafe/

I haven't played it couch co-op but the solo play has been really enjoyable

Hand of Fate

A deck construction game where the cards you choose to put in the deck are the challenges you will face on your run. You unlock more cards by completing challenges on the cards you have.

You can skip the first one and play the sequel, it's more polished.

Bugvasion TD (9 reviews)

It's a charming little tower defense game where you fight bugs with very fun abilities. I also play tested it so I may be a tad biased but I think it's underated and fun :3

I recommend Scavenger SV4 It's a very unique game where you send a rover down to a planet to grab what alien artifacts you can before your radiation exposure gets past the point it can be treated. You can bolt some of them onto your rover to make it better and send it down again. It also has several hundred different endings that are decided by how much radiation you absorbed and how much loot and what loot you brought back.

Tinykin
I know you said less than 1,000 reviews but this is at 1,500 so I think it just squeaks by.

This game for lack of a better description, adorable and over too soon.

Like a mashup of pikmim, Spyro 2, and Tony Hawk Pro Skater. It's got lots of fun platforming and new puzzle mechanics in an ever adding open world that is a true joy to traverse and cute silly little side plots that make for rather grand set pieces when it all comes together. I got 100% in 12 hours but also collect-a-thons are my jam and I was plowing through the game with grin on my face for everything but the platinum time trials.

Crab Champions is a fast paced PvE shooter with roguelike elements. You basically are a crab and fight through multiple waves of enimies. You collect loot to become stronger, and there are fun boss fights. It supports co-op multiplayer, and is made by a single indie developer.

https://store.steampowered.com/app/774801/Crab_Champions/

Linux compatibility is great: https://www.protondb.com/app/774801

CrossCode, great characters and great story. Really good game.

Doom II

...wait don't downvote yet, you've gotta play it with the new ray tracing mod

Vintage Story

I've always heard it described as Minecraft meets Primitive Technology. I would say that is quite accurate. Maybe some (optional) Don't Starve like elements where you have to worry about the temporal rift (sort of like insanity) and drifters (largely at night).

Technology progression is much slower than Minecraft. Also much more involved. Want a stone axe? You have to place a stone on the ground and use another stone to knap it into shape first. Make an iron shovel? You have to heat up the ingot first and then beat it into shape on an anvil. If you are too slow and it cools down you have to heat it up again.

Farming has 3 nutrient groups, so fertilizers and crop rotation is important.

Leather making is a multi step process of soaking hides in various liquids.

It has a built in and very extensive guide/wiki. It also has a native Linux build.