This kind of stuff follows Zipf's Law so it's 100% expected that there will be 3-4 instances aggregating the largest amounts of traffic, but instances smaller than that will constantly shift around and grow, organically, rather than be compounded and corralled artificially by one platform. In other words, this is just statistics playing out and we're nowhere near the end.

Call me when its 5 sigma.

If you like space, you should play Homeworld and its sequels. Incredible game.

If you like chill strategy, try Terra Nil, Islanders, and Terrascape -- they're all really fun and Terrascape has turn-based multiplayer!

If you like puzzle games like Myst, Cyan has Obduction and the slightly controversial Firmament, which I thought was a lot of fun. Quern - Undying Thoughts is in the same vein and feels a lot like Myst or Riven.

If you like Halo's multiplayer with an added Portal gun, try Splitgate. The developer isn't going to be adding more content as they are shifting focus to a new game, but it's still really fun.

If you like boomer shooters, try Amid Evil it feels like Quake, Unreal, and Hexen/Heretic. It'll get your heart racing for sure.

Still waiting on that 5 sigma.

Back before Gearbox, Homeworld was pretty indie and niche. I dunno if it's considered that any more, but I wanted to include it just on quality alone.