I've always loved Yoda.
He is quintessential Star Wars. I mean, he's from a species that doesn't even have a name!
Living 900 years would have a massive history to explore with regards to growth development, trails, and adversity. And the earliest years would be the most interesting, years of training to understand the Force and overcome his own dark side.
Perhaps he's from a long lost race of Force-Wielders on par with the Mortis Trio (The Father, The Daughter, The Son) or the Bendu. Or maybe a race whose homeworld was wiped out by the Sith, with only a handful of survivors scatter around the galaxy (a la Jedi Purge).
These were some concepts on a young Padawan Yoda.
