What kind of creature is yoda?

Question

I've always wondered why there was only one creature like yoda in the star wars movies. Was he really one of a kind or does he appear in other media?

I'm trying to determine if there are enough of his kind to divulge a race.

Answer 1

Quoting from the wiki:

For reasons unknown, George Lucas maintains a strict policy of keeping the history, name, origin, and whereabouts of this species unknown.

When asked what species Yoda is, Lucas has only joked, "He's a frog."

There was another of Yoda's species on the Jedi Council during the events of The Phantom Menace. Her name was Yaddle.