Granamyr appears in only four Filmation episodes across the entire 130-episode run. He is not a Heroic Warrior, not a Mattel toy line tentpole, and not a recurring threat. He is an ancient, sorcerously powerful, deeply misanthropic dragon who agrees to help on his own terms or not at all.
He is also, by a substantial margin, the most fondly remembered one-off character in the Filmation run. The reason has less to do with screen time than with character writing: Paul Dini and Larry DiTillio gave Granamyr a coherent moral framework, real grievances against humans, and a willingness to be persuaded by good faith rather than power. Granamyr does not fight He-Man. He listens, then makes a choice.
The character has been periodically revisited across modern continuities. The 2002 MYP series brought him back in a single substantial episode. The 2021 Revelation continuation reintroduced him with a serious dramatic register that the Filmation episodes had laid the groundwork for. The Masterverse and Classics toy lines have both produced full-scale Granamyr figures - notably the 2014 Classics Granamyr, which at over a foot tall is still one of the largest action figures Mattel has ever produced.