First up is Skeletor, this cel is a large profile image of the Overlord of Evil. It's actually an unusual angle we rarely see Skeletor viewed from. He really fills the frame since he's positioned in the foreground. The cel has the marking MU117 which tells us it's from the episode Beauty and the Beast from the 2nd season.
The final cel for today is of Evil Lynn. Now, this cel is marked as Stock, which means this image was developed to be used in sequences in multiple episodes. Lynn is also in the episode Beauty and the Beast, but I'm not sure if this stock cel was used in that episode.
I have all three of these cels displayed on a production background that is labeled as being from MU107. This episode is called No Job too Small, but on a quick scan of the episode I couldn't find the scene it was used in.
Here are the three cels on top the background as I have them framed in my house.
Below are two screen captures from Beauty and the Beast from the scene in which Whiplash and Skeletor converse.