Where is "posting a screenshot of the games I'm playing" guy when you need them?

Subnautica has some nice scenery, though for a painting I'd probably go with something like the safe shallows where there's plenty of sunlight, or maybe the underwater islands or the kelp forest.

MInecraft would have a lot of possibilities, particularly with some of the new terrain generation for mountains as well as the cherry tree biome that was recently added. However, with each world being generated randomly, there's no definitive scenes that would be instantly identifiable as Minecraft. So you'd have to rely on making the painting sufficiently blocky and/or replicating some of the terrain generation quirks like the occasional floating tree or lava flowing out the side of a hill and things like that.

Anything from Ghost of Tsushima.

Blood Gulch from any of the original Halo Trilogy games.

The bridge in Shadow of the Colossus, crumbling and ancient yet still striding as a titan across the vast landscape

The opulent neo-classical Indian cityscape of Sonashahar in Pacer

The Hanging City in Outer Wilds, clinging to the underside of a hollow world's fragile shell

Also, like, all of A Highland Song. It's intentionally designed to look like landscape paintings anyway. The castle in the loch is probably my favourite, or maybe the giant dam

Anything from Journey, but especially at dusk before you jump down into the dark area or the very end

The area with the giant metal tendrils in Horizon Zero Dawn

The Clockwork Mansion in Dishonored 2

Oblivion. It kind of already has that paint aesthetic, especially if you choose the setting with the quest where you enter a painting to rescue the painter.

The painted world in that one side quest in Oblivion.

You could take a photograph there, frame it, and then say you painted it.

Any random location in Elden Ring. The aesthetics of the game are done in such a way, it's meant to invoke images of renaissance period paintings.

The title screen of Disco Elysium. It kind of looks like a painting alreday.

The first Halo

Green Hill Zone

If you want another CS level, ~~Italy~~ Inferno has a ton of photogentic spots in both Source and GO. I'm also particularly fond of Lake, but that might be partly the 500 hours of Wingman on the map speaking.

Edit: or for Valve games in general, theres the dam from Half Life, Ravenholm or the drained shores from Half-Life 2, or an overgrown chamber from Portal 2.

Anything from breath of the Wild or tears of the kingdom.

Mirror's Edge

Literally anything from Elden Ring SOTE

Nearly anything from BioShock Infinite

Anything from RDR2.

City 17 from Half-Life Alyx, specifically the part where you see the tower

Here are two that I thought were particularly striking visually.

Brothers a Tale of Two Sons: The site of a battle between giants, where you had to navigate among bodies fifty feet tall.

Alice Madness Returns: The ice level, where you could see sea monsters frozen in the ice. (Ignore the text; I couldn't find a better screenshot.)

The STALKER series have very good atmosphere

I liked that bit in Oblivion where you jump into a painting and it's a painting pastel world and there's a painting troll and you fuck his shit up

Any snapshot from Morrowind.

The landscape when you get out of the first cave in Elden Ring

Red Dead Redemption 2. Pretty much anywhere.

There are certain points in Metaphor: ReFantazio where the characters stop on their journey and admire fantasy scenery which are essentially static backgrounds. I'd take a large print of any of those for my walls at home.

If it must work as a work of art absent of all cultural context, I'd say... Clock Town from Majora's Mask. Scenic little medieval town, but the oncoming angry moon tells a story

If art-that-only-works-with-cultural-context is valid... E1M1, that first moment with the blue carpet and such. I can think of very few more iconic starts to a game. Look at it and you know exactly what you need to do with the game.

Xenon map from Cube2:Sauerbraten FPS.

Guild Wars (the original base game) made extremely good use of clear visual themes and bloom to create an absolutely entrancing visual experience. It was a pretty shit game, though.

There are a few carefully planned reveals in skyrim that live in almost all our heads (one really memorable one for me is heading into the Rift and transitioning into autumn themes for the first time).

Cheydinhal is absolutely breathtaking in Oblivion.

Pretty much the entirety of Stray - outside the village areas they put a lot of effort into dramatic art reveals.

Ocarina of time has a few excellent ones but it's low poly and may be hard to appreciate at this point. Especially Hyrule Castle creeping over Lon Lon ranch and the frozen Zora kingdom.

Gosh I feel like I'm missing so many others... though on the topic of CS de_infero and de_cbbl were some of my favorite visually.

PlayStation Final Fantasy is cheating, so let's say Horizon. The ruined landscapes already tell a story (with many buildings from the real world), so it's a pretty good fit.

2D games count too, where I'd give Ori as an answer. The game creates a great fantasy world.