Undertale: It set the bar of what you can achieve in video games as a single person. It's deeply creative, charming, funny and one of the few games to truly subvert their outward appearance. And the music is perfect.
Bastion: Supergiant Games are perhaps one of the most wonderful game maker out there and this is where it started. It's deeply atmosphaeric, outright beautiful, has an extremely fun core gameplay loop and the narrator blows it out of the water. The world appearing under your feet is such a terrific effect, it stunned me when i first played it.
Dota 2: Yeah. It's a rage inducing, highly stressfull, super competetive game that requires an absurd amount of knowledge and practice to even get the basic shit done.. but there is nothing quite like it. Making the right play in Dota is an adrenaline rush that is just intoxicating. The skill ceiling is practically infinite, and it still somehow retains a bit of the charme of a game developed by some modmakers in the mid 2000s. I'm playing this shit since 2008 and keep coming back to it.
Dark Souls: I've tried like 5 times to get into it. After the 5th time it clicked and the rest is history. I'm grateful it exists and that is has gotten so popular. It showed that there can be success outside the repetive Ubisoft-"gameplay" garbage they've been selling us for years. That respecting the players intelligence and skill is a virtue, not a fault.
Nuclear Throne: Just throwing a lesser known game out there. It's a chaotic, unforgiving (notice a trend?) , excstatic top-down roguelike shooter. It's the perfect "one more round" game, it's surprisingly deep, tactical and just straight up fun. Vlambeer were a developer duo that excelled in arcade-y, lo-fi, shooters and this is their masterpiece. It's also pretty funny and has some cute lore. If you got some time to kill and like to shoot things, this is it.
I think it should be noted, that many groups of XR are locally organized and may have their own politics ranging from lib-light to actual anti-capitalist/communists. I've definitely seen local XR accounts tweeting stuff like "capitalism is the root of our environmental catastrophy and there will be no solution without abolishing it", which is at least at a superficial level better than the pure lib approach.