The real life "Indigo Children" were a sort of New Age pseudoscience conspiracy that offered paranormal explanations for about strange children who demonstrated mysterious aptitudes and other abilities.

Source: https://boingboing.net/2023/03/03/the-new-hellboy-movie-has-found-its-star.html

The series will seemingly tap the classic concept of a journalist investigating the ever-expanding reality of an urban legend, but the comic makes it clear from the outset that the Indigo Children are very real and very powerful.

Source: https://screenrant.com/scifi-comics-like-umbrella-academy-indigo-children/