In the first half of the 20th century all Hollywood spectacle films were made by Cecil B. DeMille. Make that all spectacle films. Who except movie buffs ever heard of e. g. Giovanni Pastrone and Cabiria (1914) or Abel Gance and Napoléon (1927)?
All silent movies were comedies, and had nothing but the likes of the Keystone Kops and Pie in the Face gags.
A famous German film director? Must be Fritz Lang. Very occasionally Leni Riefenstahl. These days, its more likely to be Werner Herzog.
All films from India and Pakistan are Bollywood films.
If you are going to reference or parody a non-mainstream director, it would be Jean-Luc Godard, despite the fact that the director isn't exactly "anti-mainstream" in recent years or even the most "cult" example ever.
95% of James Bond parodies are a parody of the Sean Connery era films. The remaining 5%, at least nowadays, are the Bonds of the nineties and two-thousands; Pierce Brosnan or Daniel Craig. Roger Moore, George Lazenby, and Timothy Dalton? Who are they? (If you grew up at any time between 1975 and 1995, feel free to mentally delete Roger Moore from the above list. He was undoubtedly the most successful James Bond of the late Cold War years.) The one-film Lazenby is ALWAYS mentioned whenever someone wants to sound extremely knowledgeable about the Bond Franchise.
For porn films, many people automatically pick Debbie Does Dallas or Deep Throat, although they were made in the 1970's. For actresses, they pick Linda Lovelace (or more recently, Jenna Jameson). Male actors are almost always just Ron Jeremy or John Holmes. At all other times references to specific pornographic films will typically be limited to Parallel Porn Titles (whether real or fictional).
All teen comedies were by John Hughes. (Amy Heckerling might get a mention if the reference is a little more "indie.")
Speaking of that, you would have a hard time finding a casual John Hughes fan who could remember any members of his repertory of teen actors other than Molly Ringwald, Anthony Michael Hall, Ally Sheedy, Emilio Estevez, Judd Nelson, Jon Cryer, or Andrew McCarthy, even though there were many, many more. (And no, knowing the name of a character, such as "Long Duk Dong," doesn't count; the person has to know the name of the actor.) And that doesn't even include young actors who became famous outside of Hughes's works, and are associated with him only due to Retroactive Recognition (Robert Downey, Jr., for example). Lampshaded by the 1997 book Pretty in Pink (about 1980s teen movies), which ended with an appendix listing many of the unsung Brat Packers that was wittily titled "Don't You Forget About Me."
Notable exceptions of this trope from films and this trope Played With in film:
Quentin Tarantino's movies are full of shout outs and homage shots to movies most people do not even know exist, such as Goke, Body Snatcher From Hell, where he got the idea for the red background during the flight scene in Kill Bill Vol. 1.
The indie film Little Miss Sunshine features a Proust scholar as a main character. He talks about Proust during an important character moment.
Parodied in the 1965 film version of The Loved One, in which Dennis Barlow romances Aimee Thanatogenous by quoting classic poetry to her and claiming it to be his own work.
In The Great Muppet Caper, Animal is described as being upset that he missed the Rembrandt exhibit at the National Gallery. Animal corrects him; "Renoir."
A rare humorous moment in Se7en, when Brad Pitt's character has never heard of the Marquis de Sade, and mispronounces his name "Shah-day", like the Nigerian singer Sade.
Lampshaded in Dogma with an appearance by the Metatron, the angel who speaks for God to humans who would be destroyed by the power of God's voice. The heroine attempts to make up for not knowing who he is by mentioning the Ten Plagues, to which the Metatron remarks "You people! If it's not in a Charlton Heston movie, it's not worth knowing, is it?"