They were VHS releases of episode-collections.
To make them more entertaining, Filmation went that extra step to produce new animation to have a bridge between the episodes.
The Greatest Adventures of All
showcased the Sorceress narrating between episodes
Episodes are from season 1
"Diamond Ray of Disappearance"
Had Skeletor talking to Evil-Lyn and Beastman about new characters showing up to help He-Man, and what new villains he would recruit. (this one has lot of great expressionistic animation with Skeletor)
Episodes were from season 2
"The Day of Machines"
"The Cat and the Spider"
"Trouble in Trolla"