Person of Interest to The Flash
6 connections
Person of Interest
Fringe
In the pilot of Person of Interest John Reese's suspect Diane Hanson has emails numerous characters from Fringe
The X-Files
Fringe makes reference to The X-Files classification of files.
Homicide: Life On The Street
Homicide's John Munch questioned The X-Files' The Lone Gunmen.
Law & Order
Law and Order and Homicide crossed over on four episodes
Arrow
Hudson University is the fictional University where many Law & Order characters graduated as well as the location of F.I.R.E.S.T.O.R.M. On Arrow
The Flash
Arrow spun off The Flash