The Outer Worlds

EDIT: Did you mean you DON’T want it to be space themed?

Unreal and Unreal Tournament (the latter only has single player with bots) got officially free the other day. You can get them at oldunreal.com.

No One Lives Forever has been abandoned for a while. You can get them at nolfrevival.tk.

Call of Juarez: Gunslinger

Far Cry series

Wolfenstein: The New Order

Ravenfield: free to try early version: steelraven7.itch.io/ravenfield

40% discount on the complete one: store.steampowered.com/app/636480/Ravenfield/

Someone has already mentioned DeusEx - Dishonored games also fit the category. If you are into grounded wilderness survival experiences, I recommend The Long Dark. If you are into SciFi and just don’t like space as a setting, try Metro and S.T.A.L.K.E.R. series. None of these are indies though.

Modern reboot of Wolfenstein (The New Order, Old Blood and The New Colossus) are also quite fun and brilliant - they do occasionally send you to space though (there are levels on the Moon and Venus). The recent Indiana Jones game from the same studio (Machine Games) is really good as well.

• Metro series (very good, contains creaures/mutants but also a lot of enemies are human)
• STALKER series (very good, contains creaures/mutants but also a lot of enemies are human), some mods recommended because the base games are a bit “unfinished” for lack of a better word, but the modding scene is great and always kind of saves the games
• Deus Ex series (I’ve played 1, Human Revolution + Mankind Divided, all very good)
• Wolfenstein series (the newer titles are very good in general, except Youngblood)
• Dishonored series (very good)
• Sniper Elite series (I’ve played 2-4, they were very decent)
• Far Cry series (I’ve played 1, 3-5 + New Dawn, they were very decent)
• Deathloop (interesting conceptually but also not amazing)
• F.EA.R. series (great horror/scifi themed FPS)
• DUSK, Ion Fury, … (and in general lots of other boomer shooters, lots of them are great, these are just 2 examples which I fondly remember. Lots of high quality indie games in this category)
• Cyberpunk 2077 (as an FPS-RPG hybrid, very good since version 2.x, especially with Phantom Liberty)
• RAGE 1+2 (don’t remember much from 1 anymore, but I finished it so it was at least okay. 2 was short and unimpressive but still works as well, it’s nothing impressive but if you just want a sci-fi singleplayer shooter they’re alright I guess, and they’re probably very cheap these days)
• The Division 1/2 also work decently in single-player, although some late-endgame stuff like Raids requires multiplayer. Might not count as FPS since it’s 3rd person by default, but it plays very close to FPS and IIRC you can change camera view to 1st person and when you aim from cover (which is most of the time) it feels like FPS regardless. I played both for a bit and it was better than expected but it’s also bland and gets boring after a while. Still a somewhat decent “realism”-based shooter
• Theoretically Call of Duty but I’m still not going to recommend them because of unethical developer, low value in general, inflated prices in general, short lengths in general, and so on

Right now I’m enjoying Witchfire. Although it’s not just FPS, the FPS part is good, along with the atmosphere of medieval-inquisition times and a powerful witch yet to be faced.

Gameplay consists of sessions on several islands where you kill enemies, clear up events and gradually unlock new game parts. On successful extraction you bring back witchfire (the same thing as souls in Dark Souls) to spend on increasing of one of six characteristics.

There are a bunch of weapons unlocked through research and each upgradable up to 3 tiers, by completing requirement tied to each gun.

It is fun and keeps me engaged for several days already. But if you’re not into repeating runs and rather play story based FPS, or don’t really like the theme, maybe it’s better to pick something else.

The Wolfenstein series isn’t indie, but meets your asks. It’s an alt history FPS based in WWII, so most creaturish you’ll get is dogs.

Outside of that fallout and borderlands weren’t mentioned yet, but both have rpg elements and creatures. Fallout is alt history USA while borderlands takes place on another planet.