The one that immediately comes to mind, as I was already thinking about it moments before I read the thread title:
Half-Life: Alyx for PS5/PSVR2. The game is so annoyingly inaccessible, because it requires a pretty good PC and VR head-set. Bring it to PS5 VR and at SOME more people can enjoy the game.

Numerous Sega Saturn games for any modern hardware would be good, especially the Panzer Dragoon trilogy, but also a port of the Saturn version of NiGHTS, Virtua Fighter 2 and Sega Rally Championships.

Nintendo's NES, SNES and og Gameboy catalogue on GOG. I think video games that have had such an astronomical influence on the industry and the technological development of the artform, should just be available everywhere by law really. Sure, we can emulate them, but there should be legitimate ways to get them too without signing up for some subscription service.

Its not worth it anymore.

The game isnt the same as it was in the 2000s nor the late 2000s/early 2010s where it reached its peak popularity among private server scenes.

Not so much. Source 2 is a remarkably optimized engine to where even when the game originally released, it had very moderate minimum requirements such an i5 processor, 12GB of RAM, and a 1060 GPU. To run the game in 2025, you're bordering potato territory of a PC. Probably can play it on a laptop you already have lol.

Plus it will run on a PSVR2 headset that you already own now that Sony made the headset compatible on PC. So you're really not spending much. You would probably be spending about what you would on a PS5/PSVR2 combo if not less lol. Though I do agree it's odd that Valve has not ported the game to other VR platforms.

If you don't want to play the game in VR, there's also the noVR mod. Game is fully playable from beginning to end in traditional first-person camera and still supports things like achievements.