So they said that there's plans this year for one character who wasn;t made into a figure by Palisades, and that it was an important character, yet they seemed to state that it won't be Walter, and I think I saw something that said that only characters from The Muppet Show are planned for this year.
With that in mind, it can be hard to figure out who it is (especially if the character is "important"). The closest I can think of would be somebody who was primarily featured in the first season. Maybe also Annie Sue, maybe also Louis Kazagger. Foo-Foo is kind of important, and wasn't made into a Palisades Toy, maybe it's Foo-Foo.
Or I wonder if it could be Mahna Mahna and/or a Snowth. Palisades released them as PVCs and planned to release them as action figures but never did. And they seem to have become slightly more important since the Palisades era ended.