Gwen (from the episode of Sofia the First called 'Gizmo Gwen', season 103
, episode 10, on Prime Video) had a surprise cameo on Elena of Avalor, in the episode called Class Act (Season 103
, episode 12, on Prime Video). It shows her prominenlty for a few seconds right after Isabel arrives at the college.
Note that Amazon seasons are shorter and hence more numerous than the actual seasons.