Three Early Animators 

George Melies' was a French illusionist and a film-maker, His most famous work is "Trip to the Moon" which involved a group of people travelling in a spaceship to the moon to explore it, His other work was "The Impossible Voyage" which both involve space travel. He accidentally discovered stop trick, which is when something seems to dissapear and reappear somewhere else in the same scene.

                                                  This is a video of George's Work:

Winsor McCay, was an American cartoonist and animator who created a comic called Little Nemo, He is most famous from his animation called "Gertie the Dinosaur" which is considered the first original character with a personality.

Here is a video of his work: 

Lotte Reiniger is a silhouette animator and movie director, she made short films/movies using cutouts and pupettes. One of her famous animations is called The Adventures of Prince Achmed
Which was made with carboard and thin sheets 

                                           A example of her work is below: