Martin Luther King Jr. often used characters in his sermons.
Given that he was a Baptist preacher, they were usually biblical figures, like the 12 apostles, Moses, and Lazarus. But he also drew from a wide array of innovative thinkers, both ancient and contemporary.
He cited Plato, Socrates, and Aristotle.
He explored Hamlet and Macbeth and Rip Van Winkle.
He quoted poets with three names — Henry David Thoreau, William Cullen Bryant, James Russell Lowell.
But most frequently, he spoke of politicians and activists — often his friends, sometimes his heroes, and even his enemies.
I looked through 13 well-known King sermons, which admittedly is not comprehensive. But the sermons span from 1953 when he was a guest preacher at his uncle's Second Baptist Church in Detroit to a handful in 1968, right before his assassination. I think these 82 people give a decent of idea of the people he included as characters in his sermons.