To find aliens, look to the YIMBY parts of the galaxy: "Some regions of the galaxy may be more densely seeded with those planet-making ingredients than others, and scientists are now working to understand how much galactic neighborhoods influence the planets they harbor."
The Best Neighborhoods for Starting a Life in the Galaxy | Quanta Magazine
Some neighborhoods in the Milky Way may be better suited for making habitable planets than others.
quantamagazine.org