Invisible Hand

That neigbor city's extremist ESP group, "Invisible Hand" is looking for trouble.

Monster Association Arc
During a flashback section while Fubuki is battling Psykos, Psykos reminisces about her ascension to power before going mad after receiving a revelation with her Esper abilities of clairvoyance. She mentions that they are an extremist group, implying that they are either criminals or possibly wish to replace humanity with themselves. She also mentions that it was "The right choice to leave them alive," implying that either she or Fubuki's school-day Esper group came into conflict with them and won. It is also noted that they recruited the Invisible Hand. Their current whereabouts or status is unknown.

Trivia

 * The Invisible Hand bears resemblance to Claw from Mob Psycho 100, being an extremist group of Espers. Though seeing as they were implied to be defeated by a Fubuki and her group of Espers as high schoolers, the Invisible Hand is much weaker.
 * The Invisible Hand apparently said, "You're just a student's play group" to Fubuki's Esper Group, so it is possible that Psykos was merely being overconfident when she "left them alive." Though they must have been impressed with Psykos's power to have accepted her recruitment.