Grey knights telepathically analyzing the thoughts of millions of people and plucks a single thought

"Graucis' mind had explored these streets several times prior to his physical arrival on Hyades two days earlier, but not as often since. He had sent his mind to spend time in the lesser polities too, those loyal to the Imperial governess as well as those aligned to the rebels of the Consortia, and only confirmed for himself what he had already felt.
…
He could cast his mind across the infinite voids of the immaterium and orbit a distant world, brush against the psyches of the millions who dwelled upon it and pluck a single thought from their collective consciousnesses."

-Angron: the Red Angel