Some examples of authors who are pantsers
Diana Gabaldon, author of Outlander
Matthew Hughes, author of What the Wind Brings
George R.R. Martin, author of Game of Thrones
Isaac Asimov, author of I, Robot (and many more)
Rex Stout, author of the Nero Wolfe Series
Sally J. Ling, author of Frayed Ends and Unraveled
James Joyce, author of Ulysses
Stephen King, author of IT, Carrie, The Shining, and many more
Mark Twain, author of the Adventures Of Huckleberry Finn
Ernest Hemmingway, author of A Farewell to Arms
Dean Koontz, author of Odd Thomas
William Gibson, author of The Peripheral
Stanislaw Lem, author of Solaris
Margaret Atwood, author of The Handmaid’s Tale
Hilary Mantel, author of The Mirror and The Light
Jami Gold, author of Stone Cold Heart
Neil Gaiman, author of American Gods
David Morrell, author of Rambo
Raymond Chandler, author of The Big Sleep
I personally know pantsers, plotters and something in between
The majority of people working in the comic book industry, (in my experience),
have not everything planned.
The Marvel method is also something to look into, a lot of ideas by Stan Lee
have been changed completely by the artist who was working on it and then
adjusted later. I wouldn´t call that a plotting method 