One of the T.V news reports involves a giant squid-like creature being washed up on the shoreline at Providence, Rhode Island. Also doubles as a Shout-Out to The Bible, as a massive sea creature washing up on shore is a sign of the Biblical Armageddon.
One of the books for learning hacking says something about "Don't Copy That Floppy", a old PSA about anti-copyright infringement laws, back when floppy disks were the standard data storage device.
One of the ads on the Deb of Night radio broadcast is for a line of toy robots that transform into office devices (stapler, coffeemaker, optical mouse) and form two warring factions. The ad even identifies them as a spin-off of a toy that debuted in 1984 and "became an instant classic."
Some of the passwords:
In the medical clinic, the password for the "administration" folder is "lakers", and the one related to the morgue is "cowbell".
"antoniobay" on the Elizabeth Dane is another reference to John Carpenter's "The Fog".
The password you're instructed to use by Mitnick to hack Megahertz Computing's net security is "gil bates", either a reference to previous Troika title Arcanum or directly to Bill Gates. Later, during the same quest, Metalhead Industries use passwords based on Metal music, including "turbo lover" and "bang your head".
The Werewolf sequence practically tears half the pages out of the Terminator's book. Superhuman, nigh-unstoppable, and with its only goal being to kill you in the most violent way possible. The method to killing it even mirrors the Terminator's death, albeit with a sliding observatory door rather than a hydraulic press.
You can find a Computer skill book in the Ground Zero cafe titled "The Cowboy's Guide to Cyberspace by Case" - a reference to Neuromancer's protagonist, "console cowboy" (hacker) Henry Dorsett Case.
In the Hell Hotel level, obviously an homage to The Shining, the ceiling has collapsed right in front of Room 217 (which was replaced in the film by Room 237).
The clock in the PC's apartment is a "Zaphod" brand clock.
The bum with the "End Is Near" sign is (among other things) shouting lyrics from "The Dead Flag Blues" by Godspeed You Black Emperor!. In particular, he screams about "The sewers are all muddied with a thousand lonely suicides!"
A very subtle one, but everyone who has ever taken a contracts class in law school will recognize the name McGee, from the famous case Hawkins v. McGee. McGee was a doctor who operated on Hawkins, promising to remove a scar from his hand by means of a skin graft, but who instead mutilated his hand. In the game, McGee is instead one of the victims of Gimble, who cuts pieces off of him.
Knox's design is also a visual shout out to a different work. His hair, facial design and color scheme are all heavily based on Riley Finn from Buffy the Vampire Slayer. Riley was also written out of the show with a storyline where he was willingly letting vampire suck his own blood, in an inverse of Knox's role.
In a minor side-quest in Hollywood, LaCroix asks you to make a critic's review of an Italian restaurant to be a bad one. If you are playing Malkavian and have enough dots in Dementation discipline you can use "Maggots. You are eating maggots." Line from '87 movie about vampires — The Lost Boys. You even get to lampshade it in a subsequent dialog choice:
Tommy Flayton: This place will pay for this! As sure as my name is Tommy Flayton, they'll never serve food in this town again! Malkavian PC: How could they do that to you? I bet they didn'tget that idea from a movie.
Mitnick the computer hacker is a reference to Kevin Mitnick, previously one of the world's most notorious social engineers. He now runs an IT security consulting service.
The network you set up for Mitnick in one of the sidequests (on which all the in-game Nosferatu, save for your PC if applicable, have e-mail accounts) is called "SchreckNet", a clear reference to Max Schreck, who played Orlok in... Nosferatu.
The ghoul called Romero has zombie-killing as his profession, which is the the plot to Cemetery Man.
The NPC who hangs out at the convenience store in Hollywood ranting about "piznachos" (and who later calls Deb on the radio) is called Spicoli.
One of the computers in the Ground Zero internet café contains a directory featuring short biographies of famous Hollywood actors, all of whom are thinly-disguised expies for their real-life counterparts (Jon Revolta, for example, had his bio removed at the request of the Church of Solicitology). Even a minor character, Ash Rivers, is a stand-in for Robert Downey Jr.: Rivers is a successful Hollywood actor with a history of problems with drink and drugs, whose star-making role was in an L.A.-set drama film called Negative Zero. His name is a reference to River Phoenix; at one point, the Malkavian PC can refer to him as a phoenix in dialogue. His night club, the Asp Hole, is also a reference to Phoenix's Viper Room.
During your exploration of the sewers, you can find a newspaper and a logbook discussing three missing sanitation workers, implied to have run afoul of the Nosferatu. Their names areWhitman, Price and Haddad.
The name of the food critic, Tommy Flayton, is suspiciously similar to that of real-life chef Bobby Flay.
The dialogue option of "Did I just fight a landshark?" is a pretty obvious reference to the old SNL skit.
At the Giovanni Mansion, Christopher's dirty little secret is that he's a bastard, the son of a writer named Michael Avellone. Thus making him "Chris Avellone". This callout is particularly amusing in hindsight, as Chris Avellone is now working as a writer for the game's upcoming 2020 sequel.