FlashForward to Hawaii Five-O
8 connections
FlashForward
Lost
Oceanic is mentioned in a billboard on FlashForward, mentioning it's perfect safety record
Veronica Mars
In an episode of Veronica Mars, Veronica's fortune cookie had the numbers that won Hurley from Lost the lottery.
The X-Files
The mugshot of Malcolm T Wiggins from the X-Files episode "Titonus" appears on the wall of a police interrogation room in the Veronica Mars episode "Leave it to Beaver." Also the fictional car rental company Lariat where Mulder & Scully always rented their cars was featured prominently on the Veronica Mars episode "Rat Saw God."
Homicide: Life On The Street
Homicide's John Munch questioned The X-Files' The Lone Gunmen.
Law & Order: Special Victims Unit
John Munch was a detective Homicide and then SVU
Murder, She Wrote
Jessica Fletcher taught criminology at Hudson University, where various Law & Order characters attended
Magnum P.I.
Murder, She Wrote had a two episode crossover with Magnum P.I.
Hawaii Five-O
Magnum impersonates McGarrett of Five-O on the police radio