Muppet Wiki has a sandbox page for uncredited performers, most of them being ones who were uncredited on Sesame Street. Which makes me wonder: If by chance a performer only did one street scene, especially one that didn't air on a Friday show with credits, would being uncredited me much of a big deal? The show seemed to use the same credits throughout the seasons, never crediting guest stars and such, usually only crediting certain things for sake of copyright acknowledgement.
Looking at all those uncredited performers, it's amazing to see how seldom Fran Brill seemed to perform all those years she was uncredited. Now that the wiki has more firsts and nearly all the scripts, we can now know more in terms of first appearances. And Street Gang does say that Brill only did a few weeks back then (which I think was the case with most of the main performers), but seeing that Prairie Dawn only appeared in a few segments each season and that Bril's additional performances each season were few (and there's likely some right handing and non-speaking roles we don't know about), I guess it's no wonder they didn't credit her for so long (and maybe no wonder Little Bird didn't appear often). Though a lot of her performances would have been repeated a lot, I'd like to think that would count for something.
And actually, remember above when I said it seems the credits would always be the same throughout the season? It mentions Fran Brill started to be credited again in season 21, but she's also not credited in the early credits episodes of the season. I guess that's one case where they changed the credits before the season ended.
Surprised to see that Steve Whitmire wasn't credited for so long. I knew he wasn't credited in season 25, but I would have thought he'd be credited by season 29. He was first credited in season 30. Also interesting that Matt Vogel and Eric Jacobson weren't credited in their first known seasons. I was expecting Dave Goelz to have been credited in season 24 and Brian Meehl in season 25 but they weren't, either.
On another note, I used to think that all Sneak Peek Previews segments consisted of existing film/animation segments, but now I'm seeing that that was more common at first and eventually the films Oscar and Telly watch would be Muppet segments existing exclusively in Sneek Peek Previews (kind of like Monsterpiece Theater or Mysterious Theater).
Sesame Workshop sometimes lists Teeny Little Super Guy as being from season 14, but the first one actually premiered in season 15, and looking at the wiki, all of the known segments debuted by the end of season 16. There was a press release/article for season 15 that mentioned the character, but it looks like only the first two segments aired in season 15 (odd that they would announce a new recurring segment if not much aired that season). And actually, the one listed as being from season 14 in Old School Volume 3 first aired in season 15, and the one listed as having debuted in season 15 in 40 Years of Sunny Days first aired in season 16. The wiki page says there were 13 segments while the guide only lists about 8, hopefully soon we'll see soon if any additional segments aired (we have five remaining seasons where that's possible). I have wondered if any went unaired or if the source just guessed/picked a random number.