If I’m a plural system do we get to pick 3 for each of us? :)
If it’s one set for everyone, I’m going with Shapeshifting, Healing, and the third kind of depends on how this stuff works.
Shapeshifting I’d take even if I was only allowed one power. I’d finally have a body that fits. Several of them, in fact. Some might even be human. We could swap between us physically, and turning into stuff for a while just sounds fun.
Healing because if I don’t pick it I’m eventually going to regret it. Shapeshifting might already let me fix any damage that isn’t incapacitating or instantly lethal, but that only applies to my own body. I’d want to be able to help others, too.
For the third power… Magic could mean a lot of things, including many on this list. Maybe it’s a “jack of all trades, master of none” kind of deal, which I’d be fine with. A bunch of spells that cover a wide range of situations but aren’t as strong as specializing in a single power.
Teleport is really appealing. Lots I can do with it if I can take people or things with me, or set up something long-range that doesn’t require line of sight. If it also allows me to create permanent portals then we’re really going to have fun.
Or I could take Invulnerability to remove that “incapacitating or instantly lethal” weakness and really lean into being some kind of unstoppable healer. Divine Powers? Depending on what that does, it could replace Healing while also giving a bunch of other benefits. Hell, if it lets me resurrect people too, and I also take Invulnerability, then I’m basically an emergency respawn point for the entire community.
You might like the novel Singularity Sky. It’s about a planet, artificially maintained at a 19th-century tech level by its authoritarian government, which is suddenly visited by a post-scarcity civilization. Cellphones begin to rain from the sky all over the planet and whoever picks one up is given an offer: Tell us a story and we’ll give you anything you desire. One person asks for a self-replicating replicator with a fully stocked blueprint library and it ends up being extremely disruptive in many of the ways you’re imagining.