Haven to Red Dwarf
4 connections
Haven
The X-Files
On Haven Audrey Parker's boss also trained The X-Files? Mulder
Buffy the Vampire Slayer
The X-Files? Cigarette Smoking Man and Buffy the Vampire Slayer's Spike both smoked Morley cigarettes.
Angel
Angel was a spin-off of Buffy the Vampire Slayer
Red Dwarf
In the Red Dwarf episode "Psirens", the crew of the Red Dwarf come across a space ship graveyard which includes a Weyland-Utani ship, connecting it with Angel.