Before his success with the Muppets, Jim Henson made hundreds of commercials and short industrial films, often involving early Muppets. Here I've rounded up a few favorites.
Wilkins Coffee, 1956-1961
A pair of proto-Muppets (Wilkins and Wontkins) in a series of comically deadly scenarios. Pretty adorable, really -- I'd buy Wilkins Coffee, if it still existed, just to avoid violent death. The Muppet Wiki explains how these came about, and why they're so short (emphasis added):
In 1957, Jim Henson was approached by a Washington, D.C. coffee company to produce commercials for Wilkins Coffee. The local stations only had ten seconds for station identification, so the Muppet commercials had to be lightning-fast -- essentially, eight seconds for the commercial pitch and a two-second shot of the product. From 1957 to 1961, Henson made 179 commercials for Wilkins Coffee and other Wilkins products, including Community Coffee and Wilkins Tea. The ads were so successful and well-liked that they sparked a series of remakes for companies in other local markets throughout the 1960s.
Wheels, Flutes, and Crowns, 1966
Proto-Cookie Monster as the "Wheel Stealer!" Also, the Crown-Grabber appears to be an early Beautiful Day Monster.
Linit Fabric Finish, 1967
"The iron sticketh not, and it scorcheth not, because of Linit's special ironing aid, Slide-nine." -Sir Linit. Little does Sir Linit know, Slide-nine is just Vonnegut's Ice-nine in a can.
These are just a tiny, tiny taste. There are tons more on the Henson Company's YouTube channel.