Above are sketches for The Seventh Voyage Of Sinbad, the first in a trilogy of bizarre fantasy films based around the adventures of Sinbad. Fans of this film might not be familiar with the 2 cyclops fighting each other, that scene apparently didn't make it into the movie. And this was the first Harryhausen film to have Man VS Skeleton, a concept that would be further played out in Jason and the Argonauts. There's a detailed look at the making of this Sinbad film here.
Above are sketches for the second Sinbad film, The Golden Voyage Of Sinbad. As in the previous Sinbad film, this one also has a cyclops although of the Centaur variety. More artwork from this film can be seen here.
And last, here is a drawing and some screenshots of a weird group of bug demons from the third and final Sinbad film, Sinbad and the Eye of the Tiger. See more art from this film here.