I go to thrift stores often, and I tend to find a lot of Sesame plushies on almost every trip, though I don't often buy them.
In recent months, I have picked up two Kermit plushies - A medium sized Nanco Kermit, and (surprisngly) a Disney Store Kermit in
like-new condition!
In the summer, sometime after I bought my Nanco Kermit, I found a very big Nanco Kermit for (If I remember correctly) $8, though I didn't buy it because of the permanent marker marks on his eyes and tounge.
Muppet/Sesame videos are quite common, too - About a week ago, I found
Muppet Babies Video Storybook Vol. 1, and sometime in the beginning of the year, I picked up
Sesame Street Beginnings: Talk, Read, Write, which was part of some parential educational kit, I believe.
I also saw a Muppets Jack-in-the-box a while ago, but I didn't buy it because it was pretty beat up. It looked like it was from the 2000s.