We've got a Grammy & Poppa (which I hated since I always called my Dad Papa and struggled with thinking it was a bit creepy calling my FIL Poppa as his grandfather name... but it wasn't my choice). My parent's are Oga & Kique (Kee-kay), their choices and loosely derived from the cultures where they grew up.... and then mushed up through the mouths of babes
I called my grandparents Grandmama & Grandpapa and Opa & Nana. DH had Grandma & Grandpa for both sides, using the last name to clarify which Grandma they were talking about.
I agree with you that Grandma and Grandpa are kinda boring... and if you're the first and no one cares, have fun naming them! But, in our families, we were not the first and each set had strong opinions about their names so we had no say in the matter. And that was ok, cause after all, it's not my name