Zardnaar
Legend
I mean, regardless of quibbling over whether or not the "weird people" should be included-- this is how grownups handle it.
I have been known to run a race-limited game from time to time myself, though I don't normally say "PHB YES ALL OTHERS NO"... it's actually based on a specific game-type or specific world.
But I think there's a reason that most people who say "anything outside the PHB is powergaming" don't do this. It's because they don't feel confident laying out their vision for the game-- they need an external authority to validate their restrictions.
Might surprise you, but I hate like Hell that they shoehorned tieflings into the FR and DS the way they did. I am 100% A-OK with dragonborn in the FR, and warforged in Eberron, and say mul or half-giants in DS but I'd never mix them up. I see no problem with changelings or shifters in any world that doesn't specifically preclude them, like DS or... a theoretical moonless world.
Thri-kreen are a different story, because they were canonically in GH and FR before they were made playable in DS and they're one of my favorite races.
If there's enough interest, maybe beef them up? In Shroompunk, I combined them with tortles.
Not really a 5e fan, so I don't know the current meta but I like taking the OGC races on d20PFSRD and smushing them together to see what I get-- or nixing all of the planetouched races to make them human subraces.
In my experience the anything goes games don't last long because the DM often doesn't have any vision for the gameworld and hasn't worked on anything.
Or even worse has designed a world and then all the players pick weird stuff because saying no didn't occur to them.
You can look at the old game world's or even Eberron and a large part of what makes them interesting is the new races you can play.