Forgotten games recomendations?

Death Rally (1996, free now IIRC)
Duke Nukem 3D Atomic Edition (1996)
Giants - Citizen Kabuto (2000)
Indiana Jones And The Last Crusade (1989)
Indiana Jones And The Fate Of Atlantis [I] (1992)
Loom (1990)
Master Of Magic (1994)
MDK (1997)
MDK 2 (2000)
Moto Racer (1997)
OpenTTD (2004 free version of TTD)
Populous (1989)
Raptor - Call Of The Shadows (1994)
Sid Meier's Pirates! (original or 2004 version)
SimCity 2000, SimCity 3000 Unlimited (2000)
Star Control (1 & 2, maybe 3)
STAR WARS - X-Wing Special Edition (1994)
The Dig (1995)
Uplink - Hacker Elite (2001)
X-Com - UFO Defense (1993)
XQuest (1994-1996)

And last but not least:
Epic Pinball (my fav pinball game ever)
Links 2001, Links 2003 (tons of free, well done courses for both)
Network Q RAC Rally Championship
Rocks'n'Diamonds (freeware Boulderdash/Rockford clone with original and classic levels of tons of those games)

You could look for those compilations of "top 100 games from the 2000's" or 2010, or top 50 games of 1998.

here's a few big compilations
https://www.youtube.com/watch?v=2_E_7Hek9Io
https://www.youtube.com/watch?v=7FzkyMQKsM4
https://www.youtube.com/watch?v=asMPQOVK37U
https://www.youtube.com/watch?v=xeoB4ELZa8w

you could also look into https://www.myabandonware.com/ for older games(they even have a trending section that changes here and there), and if you care for flash games into https://flashpointarchive.org/.

If the games are to be on steam you can set filters on ggdeals for instance(I don't think I can link there) and set the release date for the games between certain years like 2002 - 2010, and from there you can set a bunch of other filters. For whatever reason I can't search on steamdb by release date, which is what I would've linked you if that worked.

a few more lists here
https://www.reddit.com/r/truegaming/comments/9tprde/what_relatively_obscure_games_do_you_know_that/
https://screenagewasteland.com/the-100-greatest-obscure-games-20-11/

https://www.youtube.com/watch?v=abrRdy4pXIM Evolution of Racing Games 1986-2023 (you can do the same for other genres, like evolution of fps games through the years and you'll find similar videos)

I'll try and come back to this and suggest some I think are more unknown if you can specify if the release year matters and whether it's steam only. Some of my favs I could recommend you are captain claw, jazz jackrabbit, lion king(but it's hard af so don't hate me), aladdin, hercules, american mcgee's alice, no one lives forever, global operations, screamer(racing game), carnivores, risen, gothic, bloodrayne, quake 2, oni, the longest journey and dreamfall the longest journey, outcast, I mean I could keep going, not sure how many of these are obscure tbh but I tried.

Played this year from my backlog and loved:

PixelJunk Eden - a pretty enjoyable and some relaxing game where you play as something that looks like a spider and try to reach to something like a seed. If you enjoying house music genre you probably like it.Only remembered about it then, when it got sequel tru the game demos on steam sales.

Sang Froid tales of werewolves - TD, where your trying survive tru whole december until christmas and save your sister from the curse. There kinda only 3-5 tracks in game but it's very catchy. AND ITS FREE ON STEAM! For some reasons, devs use Virtools engine that used mostly for quest so it have performance issues on win10 because of it. So if you want to run it, you need lock fps at 30 for more stable gameplay.

Miasmata - A game with a map system based on triangulation methods (one of a kind) and movement system in this game has the concept of inertia, that you need to troy used to it. Probably not for everyone. It's kind of a survival game that doesn't try to be a survival game. It's more about exploring the island and navigate it from your memory and finding medical ingredients.

Not all are exactly forgotten, just talked about less than before. But here are some! ^^

ENSLAVED: Odyssey to the West still holds up well to this day, especially the animations. Also, Andy Serkis!
Murdered: Soul Suspect has its flaws, but it's worth playing for the story alone!
Black Mirror games kinda fell out of radar, the reboot didn't help either. Still, good games! (Except maybe the reboot)
Betrayer was removed from storefronts, but it's free on GOG and worth playing!
The Darkness II is different in tone compared to first game, but I can't deny that I like it!
NecroVision and NecroVisioN: Lost Company are fun games, supernatural WWII shooters!
Nosferatu: The Wrath of Malachi is janky and in need of a remaster, but I liked the designs and ideas used in it! Should finish it one day.
Yar's Revenge, the reboot of old Atari game, Yars' Revenge. It's alright.
Death To Spies, the stealth games set in WWII and in third game's case, Cold War! Only played Alekhine's Gun. Compared to its inspiration (Hitman) it's not very good, but not bad either.
Velvet Assassin is another WWII stealth game, and very jank. Not really that good in most aspects but I still enjoyed it!
Binary Domain, a squad based third-person shooter set in a futuristic Tokyo! I liked it quite a lot, nice story and characters with enjoyable gameplay.
Can't get more obscure than Obscure! Survival Horror inspired by Resident Evil set in a high school.

But these are all still sold either on Steam or somewhere else, a lot of forgotten games are sadly removed and abandonware. If you're interested in that kind, I can recommend Wanted: Weapons of Fate and Alpha Protocol ^_^

You mean hidden gems? It is ok if it wasnt released like 10 years ago... right? If so, i have some, but i'll just list a few for now :

https://store.steampowered.com/app/2279870/Project_Nosferatu/
If you like top down action adventure / action rpg games, this is really good. You can customize and chain your attacks from 10+ types of attack variation (no i'm not lying here). I had to redo some bosses to beat the game but the game is pretty forgiving on that (they got heals). Here is my video beating the final boss if you want to see a bit of the gameplay, just dont look too much since you'll get spoiled with its attack patterns otherwise :)
You can see how many attack variation it has at the 1:14 mark.

https://store.steampowered.com/app/1561660/The_Lightbringer/
It is a 3d platformer game. The bad reviews are mostly because it doesnt cater for casual players and you must retry the whole level from scratch if you lose your 3 lives, but honestly, i dont have to retry that often. The game is quite forgiving by giving some health restores at some points. The game was enjoyable and fun, and if you like looking for secret areas, the game has it.

https://store.steampowered.com/app/1051580/Skjoldur_Story/
Zelda + kirby where you can absorb enemy projectile to use as your own. It tries to be a lite souls-like in which enemiea respawn and puzzle reset when you die, but it ends up become an annoyance. Can be challenging if you go straight to the harder paths, but you are free to explore anywhere in any order you want and do the easier ones first. It grows on me after a few hours.

Threat- https://www.youtube.com/watch?v=kndhStFG-yg&t=1s
Wordtris- https://www.youtube.com/watch?v=6AsFmgJwS7Q&t=1s
Outpost 2- https://www.youtube.com/watch?v=5Jh9GBSDgyo&list=PLMmfhvBzj4FAX4qezl_ARxd9F62vB3wPk
Dark Colony- https://www.youtube.com/watch?v=m4b4y3tU4L8

Alpha Protocol, always.

Somehow I knew it would be that video, good channel 😉
My suggestion:
Binary Domain
https://store.steampowered.com/app/203750/Binary_Domain/

Last Rites
https://store.steampowered.com/app/814610/Last_Rites/

PowerSlave DOS
https://store.steampowered.com/app/1260020/PowerSlave_DOS_Classic_Edition/

PowerSlave Exhumed (Saturn and PSX versions combined)
https://store.steampowered.com/app/1678430/PowerSlave_Exhumed/

There's this abandonware I played a fair amount of when I was a kid that I loved: Ludo Race.
No, not the 4 horses thing, a 3D racing game.
https://www.myabandonware.com/game/ludo-race-jpm

Gorky17

https://store.steampowered.com/app/228300/Remember_Me/

Maybe this?

Daemonica
A kind of detective/quest in a medieval setting. Lots of text. There are rare sword fights and they are not very good :D There is also a good story and interesting mechanics, which I will not reveal :)
https://www.myabandonware.com/game/daemonica-jia

legacy of kain and soul reaver games

Delta Force 1-2
Thief 2 Metal Age

The original X-Com was already mentioned but Terror From the Deep and Apocalypse are worth checking as well. All the old X-Com games are on steam.
Suikoden I and II are great games, they are currently getting remakes for steam.
Genewars was a game I enjoyed back in the day from Bullfrog(Peter Mollyneux). You can find it as abandonware.

The real Gladius

Generally yes, that was an idea, to find some hidden gems, but mainly PC. I has sad that some of them are not avaliable like Champions Of Norrath for example.

But my list atm.

Delta Force Black Hawk Down.
Simcity 3000.
Silverfall.

So far.

I've tried Ascend: Reborn but meh, i don't like it.

Operation Flashpoint: Cold War Crisis

Dirt cheap, still being modded (ikr?), and terribly on point with some of it's writing.

The Prince of Persia Trilogy:

https://store.steampowered.com/app/13600/Prince_of_Persia_The_Sands_of_Time/
https://store.steampowered.com/app/13500/Prince_of_Persia_Warrior_Within/
https://store.steampowered.com/app/13530/Prince_of_Persia_The_Two_Thrones/

Sunset Overdrive:

https://store.steampowered.com/app/847370/Sunset_Overdrive/

F5

Got some more ideas?

Get Dexter

Also called Crafton & Xunk where I live

How about Sleeping Dogs? If you haven't seen it, I highly recommend it.

View attached image.

The Journey Down Trilogy is fun (and I'm only halfway through it rn :p)