Bond asks who would pay a million dollars to have him killed. Quoth M: "Jealous husbands, outraged chefs, humiliated tailors. The list is endless!"
Bond asking Miss Goodnight, who's in a bikini, "Don't you think you're a little overdressed?"
Bond accidentally swallowing a spent Scaramanga bullet he was retrieving during a fight and requesting that a taxi take him to "the nearest pharmacy" afterward.
Andrea trying to explain what Scaramanga looks like so Bond can find him at Bottoms Up, and after struggling to come up with a distinctive feature she mentions his third nipple.
Bond: Fascinating anatomical tidbit. But probably the most useless piece of information I've ever heard. Unless, of course, the Bottoms Up is a strip club.....and Scaramanga is performing.
And this is after her even more non-specific and useless Tall, Dark and Handsome description, to which Bond retorts that makes a pretty good description of his aunt. Even more meta-hilariously, Bond's mention of a living aunt is the closest *thing* this movie ever gets to the literary canon, because he actually does have one (mentioned in his obituary, You Only Live Twice.)
After Scaramanga makes his getaway in his flying car:
M: So if I understand it, Scaramanga got away - in a car that sprouted wings!
Q: Oh, that's perfectly feasible, sir. In fact, we're working on one now.
M: Oh, shut up, Q!
Nick Nack giving a "So long, sucker!" look to Bond during the car chase scene. Made funnier with the look of amused contentment on Scaramanga's face.
The end scene, where M is asking for Goodnight. What is Bond's response? "Good night, sir." It feels like a pun that should've come earlier, but held back until the last possible moment.
The hitman in the opening scene being horrified at having shot a dummy of Al Capone. "Wherever you are, don't hold it against me!"
The compilation book The Incredible World of 007 gives a behind the scenes example as told by Maurice Binder, who designed the provocative title sequences for all the EON films up through Licence to Kill; they ran into a problem with one of the nude models, her pubic hair was sticking up when they needed it flat. After a few minutes of her trying and failing to get it right, the model gave Binder the brush and told him to fix the hair to how he needed it; as Binder recalls it, he was not about to pass up that opportunity. The whole thing was seen by Roger Moore and producer Harry Saltzman, causing Moore to turn to Saltzman and quip, "If you're the producer of this film, you're not getting the perks!"
When Bond's gun falls into dark oblivion, Scaramanga's facial expression is priceless. He must be thinking something like: "What the fuck was that?? The guy's gonna kill himself before I find him!"