Anywhere But Their Lips: It's only in their first scene together that Elizabeth says "Not on the lips," to Freddy, and the reason is that she doesn't want her makeup smudged.
Subverted in that she doesn't seem to want to be touched anywhere, lest she mess up her hair, her nails, her dress, etc. In the end she and Frederick say goodbye by shaking elbows. She even flinches when he blows her a kiss.
Bullying a Dragon: The prison guard when he discovers that the Creature is afraid of fire. Protip: If you're going to taunt a 7-foot tall, super-strong monster with anger issues, don't do so within arm's reach.
Cobweb Jungle: In the passage leading to Dr. Frankenstein's laboratory and the laboratory itself.
Corpsing: Was understandably a problem throughout the shoot. In several scenes you can see Gene Wilder is just barely holding it together.
Brooks has said that even more footage was shot for the film than was actually going to be used because cast and crew were just having too much fun on set that they were starting to get bummed that principal photography was coming to an end.
It's one of the rare films where the crew had issues with corpsing—the "baggage" scene made them laugh so hard that it ruined takes.
Creepy Changing Painting: A scowling portrait of Victor Frankenstein is highly visible in Fredrick's room. When Frederick finds his grandfather's instructions and decides to continue his work, a lightning-illuminated close-up shows the portrait looking very pleased.
Creepy Housekeeper: Frau Blücher (*WHINNY*) is the quintessential creepy housekeeper: every time her name is mentioned, horses rear in fear. Also, in regards to Victor Frankenstein: "He... vas... my... BOYFRIEND!"
"He Vas" Song": Which leads to her singing about Victor in the Musical, complete with Evil Laugh and vamping by Andrea Martin for "He Vas My Boyfriend." Doubles as a Villain Song as she hints he wasn't too nice a guy other than the sex.
Dark Reprise: The Musical has "Life, Life" where Frederick is trying to coax Fate to let the Monster he's assembled live, and "Frederick's Soliloquy" has the same tune, but the village is about to hang him, and here he's accepted who he finally is without regrets. The newly-intelligent Monster realizes the hung Frederick is unconscious, not dead, and is able to revive him.
Deliberately Monochrome: To better parody the original Frankenstein movies. (This was so important to the filmmakers that they took the project to 20th Century Fox after originally conscripted studio Columbia balked at the prospect of it being in black-and-white.)
Don't Explain the Joke: Averted — during the Walk This Way scene, Igor shows Frederick what he means. It doesn't ruin the joke at all, though. Supposedly, this gag was the inspiration for the Aerosmith song of the same name.
In point of fact, it worked so well, it's something of a Running Gag for Mel Brooks. It shows up in most (if not all) of his films. The walk is different, but the joke is always the same.
Hypocritical Humor: After what seems to be the failed attempt at resurrecting the dead, Frederick states that it is better to accept both loss and success with "quiet dignity and grace." Seconds later, he loses his shit and takes out his frustration on the monster, choking and hitting the corpse all while screaming incoherently; all of this is lampshaded by Igor who just repeats Frederick's "quiet dignity and grace" line.
In the Blood: "Des-ti-ny! Des-ti-ny! No es-caping that for me!"
Also something of a subversion; Frederick is doing just fine escaping the family tradition (aside from a hamtastic moment in his lecture on neurobiology) until his great-grandfather's will and then his "servant" Frau Blücher (*WHINNY*) railroad him into it.
The Musical also has "Join the Family Business" as a number where the ghosts of Victor Von Frankenstein and other ancestors iron that point home.
Frankenstein: It isn’t. It’s Frederick Fronkensteen.
Igor: I see.
Frankenstein: You must be Igor (pronounces it as Eeee-gor).
Igor: No, it’s pronounced EYE-gor.
Frankenstein: But they told me it was EE-gor.
Igor: Well, they were wrong then, weren’t they?
Just a Stupid Accent: Deliberately, this being a Mel Brooks film. The movie takes place in Transylvania (located in Romania), but the townsfolk generally have bad German or Cockney accents. Kemp's is so terrible that his own countrymen have trouble understanding him.
Lampshade Hanging: After the horses Running Gag is established, Igor stays around, listening intently, and says, "... Blücher." (*WHINNY*) Then grins with satisfaction.
Mythology Gag: The book "How I Did It". In the original Frankenstein novel, we never do hear any details of just how the monster was brought to life. All the stuff with the lightning and stolen brains was added in later adaptations. Some of the lines he reads from the book are taken directly from the novel, however.
Names to Run Away From Really Fast: Just saying "Frau Blücher" (*WHINNY*) causes horses to rear up in fright. Just the name; the woman's actual presence doesn't bother them at all.
Neck Lift: The Monster, to the police officer tormenting him.
Frederick: There's a possibility of electrocution! Do you understand?...I say there's a possibility of electrocution! Do you understand?!
Igor: I understand, I understand, why are you shouting?
On One Condition: A deleted scene explains how Frederick inherited the estate of his very distant and disliked great-grandfather: said Baron Frankenstein had left his estate to his much closer relatives, naming each of them specificially, to be divided up evenly, unless Frederick had of his own choosing become a doctor and achieved some esteem in his field. As this had indeed happened, all the money and property went to him. The idea was that the Baron wanted to give his inheritance to someone who would have some chance of erasing the stain on his family name.
Frederick also had to meet the terms before the day Baron Frankenstein would become one hundred years old. Said Baron Frankenstein left instructions that his will was not to be read until then.
Shaggy Search Technique: "Put - the candle - back!" Part of the parody is that Dr. Frankenstein was using legitimate means to search for it before the trope kicked in
Shaming The Mob: The Monster himself does it, with a speech mostly cribbed out of Shelley's original book.
Shoe Shine, Mister?: When Frederick's train pulls in, he asks a shoeshine boy, "Pardon me boy, is this the Transylvania Station?" The boy replies "Ja, ja. Track 29. Oh, can I give you a shine?" This is a Shout-Out to the 1941 song "Chattanooga Choo Choo".
Silly Will: The aged Baron Beaufort von Frankenstein leaves instructions that his estate shall be given to his distant great-grandson rather than shared among a cadre of mooching relatives if said great-grandson has become a respected doctor of his own accord. One of the relatives tries to pass this clause off as insanity but the executor reminded her that civilization is based on law. The scene was removed from the final film.
Igor's hump, which changes position from scene to scene; Marty Feldman decided to do this on his own, without telling anybody beforehand. When someone finally noticed, they added a bit where Frederick does as well.
Brooks ad-libbed the sound of a cat getting hit with one of Frederick's darts.
Almost a Throw It Out moment; in some interviews, Mel Brooks stated that the only point during production where he and co-writer Gene Wilder seriously disagreed was the inclusion of the "Puttin' On the Ritz" number. Gene loved the idea but Mel hated it. After Gene vehemently defended the scene, Mel decided, "If you feel that strongly about it, we'll shoot the scene. If it works, we'll use it, if not, we won't." They shot it and it became one of the highlights of the movie.
Title Drop: It's hard to catch thanks to Kemp's accent slurring the sentence, but it's there:
Inspector Kemp: Und... ve had better cunfeeeerm de fect that yung Fronkenshtein ish indeed... vallowing in his grandfadder's footshtops!
Understatement: In a deleted scene, it was revealed that, to be allowed to inherit his great-grandfather's estate, Frederick Frankenstein had to become a medical doctor on his own will and earn some measure of esteem on his field. A relative then asked if Frederick did acquire a "measure of esteem" and was told he's the fifth most respected expert on his field.
Video Will: Frederick Frankenstein's great-grandfather left a recorded message in an actual record.
Whole Plot Reference: The film is specifically a parody of Son of Frankenstein more than any other movie. The inspector with the wooden arm and the part where he talks with Frankenstein while playing darts are a direct lift.