birds of a feather (flock together)
From Longman Dictionary of Contemporary Englishbirds of a feather (flock together)birds of a feather (flock together)informalSAME used to say that two or more people have similar attitudes, beliefs etc → birdExamples from the Corpusbirds of a feather (flock together)• He figured I had a hustle of my own going and that made us birds of a feather.