Not what you were looking for, probably, but in Donald Westlake’s Dancing Aztecs, the entire Dortmunder crew makes what can only be called a cameo appearance to help a character in Dancing Aztecs move his car out of someone’s driveway, and they are not seen again.
Just Westlake having a bit of fun.
Ali Smith- How to Be Both
And I suppose Gone Girl?
Raymond E. Feist and Janny Wurts’ Empire Trilogy is contemporary to Feist’s Riftwar saga and contains some crossover elements.
David Weber’s military sci-fi about Honor Harrington now has a couple or three branches, where different novels and novellas, sometimes by different authors, are covering the same universe/time period (aka the Honorverse), with many characters and events in common.
Hugh Cook’s Chronicles of an Age of Darkness interlinks characters and plots, with the protagonist and events of one story being peripheral elements in another.
theres a few books from the shadowrun fiction that do this basically theres a set story and 6-8 (or more) people write it from their characters point of view in each chapter and they comment when they run across the effects from the other characters like one had a jack the ripper persona and two chapters later someone was warning people about the "damn fool who was playing jack the ripper online " and then everyone’s efforts tie into the ending chapter
Roshomon
Hoodwinked tells the story of Little Red Riding Hood from multiple different perspectives.
Dr. Jeckyll and Mr. Hyde and Mary Reilly.
Beowulf and John Gardner’s Grendel
The Wizard of Oz and Wicked
The True Story of the Three Little Pigs
In comics, Marvels shows various events in the Marvel comic universe from the point of view of a non-super reporter. (Comics do this often, with various crossover events).
In Robert Anton Wilson’s Schrödinger’s Cat Trilogy, the same cast of characters exist simultaneously in three alternate universes. So, different PoVs but same characters.
Margaret Atwood’s trilogy,Oryx and Crake, The Year of the Flood, and MaddAddam basically covers the “end of the world” from three different perspectives. It kinda flags when you get to MaddAddam, but I definitely recommend the first two.
Piers Anthony’s Incarnations of Immortality series also covers the same incidents from different perspectives in each book (particularly in the extra books written after the first five).
This reminds me: John Barnes has a series (the Century Next Door series) in which two of the books are YA (“Orbital Resonance” and “The Sky So Big and Black”) and two of the books (“Kaleidoscope Century” and “Candle”) are very R-rated (the “hero” of KC is a mercenary soldier who commits murder and rape regularly - and he’s not the worst person in the book).
Most of your examples are cases of “people writing the classic novel from a different point of view”, which I was trying to steer away from.
No one has mentioned Robert Heinlein’s pair – his last novel To Sail Beyond the Sunset retells some events from Time Enough for Love from a different POV. There are connections with other books and other Heinlein characters, but it’s that simultaneous event/ different POV thing I['m looking for.
I was meaning to mention those two - sorry.
Harry Turtledove has paired stories - “Twenty, Counting Up” and “Forty, Counting Down” feature many of the same incidents told from the perspective of two different (-ish) characters.
I was going to mention the same work. I think I spent a summer, during my off-hours, reading the quartet. It was a fascinating series because of the perspective you mention. Something seemingly insignificant in one novel, an almost incidental detail, would be incredibly important in another novel from a different character’s point of view.
As I recall, there was only one place where those “intersected”, and it really wasn’t an intersection in the way this thread is about. That point was that the main character of Cetaganda got a key piece of information that lead to the events of the other book. But since he couldn’t do anything with that info until the book was over, the two didn’t actually overlap in time.
I’m surprised no one’s mention Robert Sheckley’s “Pas de Trois of the Chef and the Waiter and the Customer”, a real classic in this genre.