I was looking through comics and the TV shows and I was wondering who trained Yoda in the ways of the Force. I could be wrong but I don't remember any mention of Yoda's master.
Master Yoda mentions his master in the new Junior novelisation of Star Wars: The Empire Strikes Back. Beyond that, there are no (Disney) canon references to the person who taught him:
Yoda chuckles. You don’t know why. You open your eyes and glance at his gnarled, withered body. His smile is as serene as the double sunset of Tatooine. “Story heard I once,” he says. “From my master. True or not, I do not know. But good story. Listen you will.” Yoda closes his eyes, inhales slowly, and begins.
Moving down the canon scale, there are references to a Hysalrian Jedi Master named N'Kata Del Gormo being Yoda's master. Leeland Chee (of the Star Wars Story Group) has noted that mentions of him are an "in-universe legend" and not to be considered canonical.
While not Yoda's master, Huyang taught Yoda how to construct his lightsaber, possibly qualifying as "training him in the ways of the force".
Huyang appeared in season five of Star Wars: The Clone Wars.
We had quite an eventful mission.
The most eventful since the time Master Yoda went to find his lightsaber crystal.
(Star Wars: The Clone Wars 5x09, A Necessary Bond)