It seems like Muppet Wiki has pages for almost every episode of Sesame Street I remember seeing as a kid back in the late-1980s and early-1990s.
There's not many left that I haven't found a page with info on (and the episodes could have pages without mentioning certain episode details I remember). One episode I remember that I can't find any info on on the wiki is one where Oscar has a trash sale (not the one from season 30). I also recall one time when Gina was crying and told Big Bird she was crying because she was so happy, I'm assuming that was around the time she graduated high school, or maybe she was accepted into college/about to enter college. I also remember a time (which could be from the same episode I just mentioned) where Susan explains to Big Bird about what Miles has to do before he's ready for college. I also remember one time, I think it was the end of the episode (and I think the episode involved daycare or pre-school for several characters), Irvine was inside the trash can Bruno was carrying, with Oscar in his can in his usual spot talking to Irvine.
Thanks to the trusted sources (and a handful of episodes that it turns out some fans had, at least partially), there are guides for episodes I remember seeing around the early 1990s (of course either season 22 or 23, can't remember which, has full guides for all but two episodes now). Such as the episode involving water conservation, I remember thinking as a kid that Hooper's Store was just out of water and thinking it was because people wasted it ("wasted" was a term I often heard as a bad thing without really knowing what it meant or how you could waste things like food or water), it was great reading about the scene where Biff fixed a faucet at Hooper's, I thought that was why they didn't have water (and I was wondering what Biff actually did... I figured he'd mess up but the guide said he just pounded it with his hammer and it got fixed). I used to think Biff and Sully were plumbers because of that scene, looking at the guide it seems like Mr. Handford just asked Biff to fix it instead of calling a proper plumber.
And it's great to see a guide for the episode where Mr. Johnson eats at Hooper's Store (which was repeated... too bad we can't have images yet). I don't remember Bob being there. I'd kinda like to see the scenes again, see what it's like when Grover called begging for Johnson to show up (I remember a Waiter Grover segment appearing, I think I thought they showed the one with Simon Soundman instead), and I'd like to see if Grover was actually shown at the end when Johnson sees Grover eating his order. Interestingly, this one has the one where Grover uses his waiter memory, and that segment would also be included in the episode where Hoots has Savion work at Birdland, showing it as an example of what not to do as a waiter... I guess they liked using that one when a Waiter Grover segment had to connect to the plot.
And it was great to read about the season 23 episode where the gang votes on whether to buy crayons or juice and Telly is the tie breaker. A short description (taken from a news article) was on the wiki, actually not mentioning Telly, I was surprised to hear about Rosita being in it, I actually don't remember her from that time. I was also surprised to see that it's from season 23, I always misremembered it coming earlier to when Mr. Handford was introduced (I briefly contemplated that maybe the plot was repeated from two years ago, but I doubt they would have repeated any street stories with the original Mr. Handford).
One episode that recently got a guide (this time with pictures) that I'm actually surprised I forgot about is one from season 25 or 26 where Big Bird makes a new friend who wants to play pirates, while Big Bird would rather play Duck Duck Goose. For all these years (that I could remember) I thought he was playing with Goldilocks instead of some new character, though it was made from the same Anything Muppet and looked similar (I'm guessing Camille Bonora performed her with the same voice). I should probably see if this one's on YouTube.
It is interesting looking at guides for episodes I remember seeing but hadn't seen in so long, seeing what sketches were included, recalling segments that I remembered seeing around the time, but also in looking at guides for episodes I don't really remember, seeing segments listed that I remember seeing at the time and wondering, "did I see this one?" Especially if it's a clip I only remember seeing once as a child before the age of the internet and YouTube (there's a few episodes with "Put It in the Trash Can", which I only recall seeing once, I keep asking myself "did I see this episode???").
I don't think there's any inserts I recall seeing as a young child that I haven't seen since childhood (in English). Then again, I do remember seeing a Miami Mice segment without Kermit or Ernie, it could be the one with The Count (which is only online in dubbed form), or could there be another one we don't have info on? Because while I remember a third one, I don't remember it having The Count or any familiar characters, but I could be wrong. And maybe someday I'll see a segment I saw as a child that I forgot about and instantly recall seeing it when I do.