Ravi mentions "D & D" when explaining what a LARP is to Clive. In the previous season, Clive and the rest of Liv's friends played a session of D & D, aka Dungeons and Dragons, in order to help Liv trigger a vision. Unexpectedly, Clive enjoyed the experience so much he tried to get the others to continue playing the game.
First episode where Liv doesn't break character after consuming a brain.
Liv mentions a few weapon names when offering Ravi a scalpel. One of those names is Lightbringer, which is from Game of Thrones, a series that Clive enjoys and that the show has made numerous references to. Lightbringer is a fabled sword thought to be made of living fire.
Liv mentions to Peyton that Fillmore Graves is like the Borg. The Borg are an alien race from Star Trek that have a collective consciousness, meaning they are essentially all forced to think the same, implying that the same is true of Fillmore Graves.