underrated or "not so popular" games

Iconoclasts and Brutal Orchestra are 2 really good games kinda underrated in my opinion

Spec ops the line

Chicory. But I don't think it's underrated, maybe just a little bit unknown.

I really enjoyed Everhood. It's a music based adventure game. A bit of a weird one but quite enjoyable.

A lot of decent stuff gets lots between the deluge of asset flips and top-notch indie games:
Chronicles of 2 Heroes
Full Void
Ravva and the Phantom Library

Etherlords II, alwa's legacy, solasta

Blood and Bacon FPS, armored hogs, farmer on the wall,
rough graphics, 1P, co-op up to 4 players, paintball, still in active development.
Eidolon Exploration, Open World, walking simulator, rough graphics,
no hand holding, collecting, reading, can & will die, 1 player.
Salt Sailing, fishing, vast ocean, exploration, pirates, loot, rough graphics,
NO naval battles, quests, collecting, crafting. 1P, 2P works sometimes.
I enjoyed playing the above games. A plus being they're inexpensive, will run on 5 year old laptop.

https://store.steampowered.com/app/1561660/The_Lightbringer/ 3d platformer
https://store.steampowered.com/app/9940/Blade_Kitten sidescroller action
https://store.steampowered.com/app/2279870/Project_Nosferatu action rpg

Driver San Francisco.

Road to Ballhalla is really great

If you enjoy point & click puzzles: The Inner World franchise. I won The Inner World on SG and really enjoyed the goofy puzzles and lovable characters.

Road Redemption - Road Rash vibe with coop multiplayer (shared screen).

I think there are many great games that are not as known, also not fully sure when a game falls under that category and also not sure what kind of games you enjoy.
I selected a few I enjoyed that didn't had many reviews, some might have mixed reviews but I enjoyed them!

• MacGuffin's Curse
• Hare In The Hat
• Cross of the Dutchman
• Big Brain Wolf
• Pan-Pan

https://store.steampowered.com/app/1700/Arx_Fatalis/
Arx Fatalis is Arkane Studios's first and most underrated game, not many people know about it

• NaissanceE, not exactly underrated but somehow not particularly well known despite being amazing.
• Hook, and pretty much everything by its dev, great little puzzle games.
• Reventure, it's a game about losing, or rather about finding the hundred possible endings... most of which are dying in increasingly obscure ways. Surprisingly addictive, and it has an absolutely absurd number of hidden secrets.

"Dominions 5" (soon 6), the best game (practically made and updated by one person).

Quest for Infamy
King of Dragon Pass

Valkyria Chronicles 3, one of the best games I've ever played in a series that deserves so much more attention than it gets. VC1, VC3 and VC4 are all absolutely amazing games (VC2 is still very good, but not AMAZING like the rest).

https://store.steampowered.com/app/1543280/Espresso_Tycoon/
I played this weekend. Very good to relax, but I found it a bit expensive, because the campaign mode ends very quickly.

The Longest Journey trilogy.
The Longest Journey
Dreamfall: The Longest Journey
Dreamfall Chapters

I had a great time playing Manual Samuel in Co-Op

Yakuza 0, trust me on this one, just get it.

The Gardens Between.

Yes, it is a puzzle with minimal input, but it is the platforming puzzle done right. There are so many things you can achieve even when the controls are moving time forward, moving time backward and interact with items. Plus, each puzzle are deeply curated, each characters have deep animations, and cleverly hidden easter eggs. Highly recommended.

If you like JRPG's these are great imo:
Aveyond Series and you should play the games that came before as well but those you'll have to get off steam. Ahriman's Prophecy, Aveyond 1: Rhen's Quest,.Aveyond 2: Ean's Quest, and then you go into the saga.
Ara Fell I haven't finished this yet, but I don't know how it's sitting at only 1500 reviews. It deserves more praise, it might be the most well done RPGMaker game out there.
Skyborn One of the first RPGMakers I played on steam as I was playing through the aveyond series and I really enjoyed it.

If you want to laugh, try
The Darkside Detective A detective game with a bunch of dad humor. This also has a sequel if you like the first game.
The Looker This is free and I honestly think you should have to pay for it because it's very well done. It should not be sitting at 11k reviews., and while that may seem like a lot, it's not considering how good it is.

If you like trading games:
Crypterion You can get this pretty cheap and it was great. Simple trading game, with VN elements.
Gazillionaire This is an old game, that they republished that basically gets no sales, try and get it elsewhere unless they put it on a decent sale or just wait until they put it on sale, great game although it looks weird af.

Murdered Soul Suspect I don't know if this can be considered underrated since it has a decent amount of reviews, but I think for what it delivered that I think only once or twice in the forums heard someone say what a great game it is.

Unavowed Great point and click game.

Super Kiwi 64 Once again, haven't finished it yet only played 4 out of 16 levels I believe, and I actually think there's no save feature so I'll probably have to do it again and if you play, I think this is a game you play in one setting, but it gave me such a old n64 vibe tbh and it was so relaxing to play. The controls were absolutely flawless.

Nomad Survival If you liked Vampire Survivors, Halls of Torment, Brotato, etc. this is a great game as well. You can also play Magical Survival on android(not sure if it's on iOS too) which is basically the daddy of Vampire survivors.

Now if you want some older games that are off steam: Jazz Jackrabbit, Oni, Captain Claw, GT-Racing 97.

Wunderling DX. I won it here on SG. When I was entering the giveaway I thought "This game looks really nice for one or two evenings - just 4 hours according to HLTB". But then I spent almost 14 hours with it.
That game deserves the title of One of the Hidden Steam Gems (at leas for all lovers of fast paced arcade puzzle games). I managed to get 40 out of 41 achievements without any guides and tips while just playing for pleasure. It is not punishing (like for example Meat Boy). It is challenging just right. I was continuously getting positive vibes from the game without any negative emotions. And the most important: while playing I physically felt that developers put love and soul into this game.