Mass Effect uses "Element Zero" which is a particle that attaches to nerve clusters and sometimes lets the user manipulate mass, gravity, and other forces in physics.
The Endless universe has nanobots left behind by an ancient technologically advanced civilization that destroyed itself. Harvesting and learning to use this "Dust" underpins a lot of the worldbuilding. Some heroic individuals end up infused with the stuff and it is the explanation for basically anyone who can do something supernatural.
In both those cases, the ability to leverage the "magic" is something that integrates into the individual, but learning to utilize it is a long running process. So your setting could have a nuclear science experiment somewhere spewing a new particle into the world, maybe it collects on certain people or maybe not, and people are just learning to how to use it.
Not including whatever Wagner got up to.