Some other characters that Jim Henson used in TV commercials during this period also provided some collectables. For example, the two puppets for Wilkins coffee were marketed as plastic moulded puppets, and a three foot tall inflatable figure of the La Choy Dragon was also marketed.
It wasn't until the mid 1960s, after colour TV came about, that Kermit became "Kermit the Frog" for a TV special, "Hey Cinderella". The pilot for this special was taped in 1965, the actual TV special recorded in 1968, and it was finally broadcast in 1970. This was followed by "The Frog Prince" (1971) and "Muppet Musicians of Bremen" (1972) both of which also featured Kermit the Frog. All three of these productions were recorded in Toronto, and were the first of a long list of Henson productions to be recorded there.
In 1970 when Hey Cinderella finally aired, a series of cheap "plastic bag" style hand puppets was produced and sold as a special offer through Hawaiian Punch drink mix. These puppets were simply an illustration of the character printed on a plastic bag shaped like a hand puppet. They were similar to those made popular by McDonalds restaurants during the same period. (McDonalds offered hand puppets featuring the McDonaldland characters as a free give away to attract families with their kids.) To my knowledge Kermit was not included in the Hey Cinderella set of puppets. More info about them along with photos have been posted on the Muppet wiki site at this link: http://muppet.wikia.com/wiki/Hey_Cinderella_hand_puppets
Here is the original VHS video release of "Hey Cinderella" in a modified video rental case next to the unmodified case for "Muppet Musicians of Bremen" from the same video series. Although the productions were recorded in the mid 1960s and early 1970s, these home videos weren't available until the early 1980s when VCRs first arrived on the market.
Here is the Video Disc release of Emmet Otter's Jug-Band Christmas and The Muppet Musicians of Bremen from 1981. They were packaged together on the same disc which is titled "Tales from Muppetland". Below is the back view.
After appearing as a Frog for the first time in "Hey Cinderella", Kermit then appeared on the very first episode of Sesame Street in 1969 and although he became a regular character on the program, Kermit was not included with the cast of Sesame Street Muppets when they were marketed in the early 1970s as toy puppets, dolls, puzzles and more. However, Kermit did appear in a few early Sesame Street books and the character's soon to be famous song "Being Green" was included on several of the Sesame Street record albums. This same series of records also included albums for the TV specials of "Muppet Musicians of Bremen" and "Frog Prince" which featured "Kermit the Frog".
This is one of the first and only Sesame Street books to include Kermit the Frog. It was published in January 1971 by Signet, which is only one year and two months after Sesame Street premiered on TV in Nov 1969.