Warren. He just disappeared. My guess is that Andy had him committed...
Ellie. I don't think her disappearance was ever explained. Strange, since she and Andy seemed to be thicker than thieves there for awhile. In fact, he actually proposed! Hard to believe she just vanished and they never told us why--or where she went.
I forgot about Ellie. It's unfortunate that she left at all. I'm guessing that her character would go on to better or bigger places.
Ellie and Warren are great suggestions. I will say Barney. I want to see what it was like for Andy and Mayberry when Barney applied for the job in Raleigh, when he interviewed and what it was like to say goodbye. It had to be emotional and a "red letter day" for Mayberry. Maybe even bigger than when the gold truck came through.
Fred Plummer....he came back several times but not who he was before. I guess Barney knocked him silly using that Judo stuff!
I wonder what happened to Arnold Winkler after his trip to the wood shed. Did he turn into a fine citizen or is he doing "time" somewhere?
I think the trip to the wood shed did do Arnold some good, as he was pretty tolerable in, 'The Haunted House' episode.