1. Plastic Man.

The original and still best. Although Plastic Man survives 'til this day in comics, no-one has ever been able to duplicate the genius of his creator, Jack Cole. A reformed criminal, Plastic Man works as a special agent for the FBI, using his unique shape-changing talents to bring down organized crime- often his former associates. He even got his own postage stamp:

Or is this just Plas in disguise?
2. Elongated Man

Despite his naughty-sounding name, Elongated Man was a fairly innocent superhero feature from the pages of Flash. Ralph Dibny, became obsessed as a young man with the flexibility of "India Rubber Men" in carnival sideshows. He noticed over time that all of them drank a particular brand of soda-pop made with extract of "gingold". Dosing himself with a powerful concentrate of gingold, Ralph discovered he was able to stretch any part of his body (!). He then decided to fight crime as the "Ductile detective", Elongated Man.
3. Elastic Lad

After taking an "Elastic Serum", Jimmy Olsen had a short-lived career as
Elastic Lad. Since Jimmy has had too many bizarre powers and shapes to list, I don't know what else to say.
4. Mister Fantastic

Okay, this is the one stretchy guy my wife actually likes. But does she like him for his cool, stretchy power? Does she like him for his mind-numbing intellect? No. She likes him because he's a pompous ass. This explains SO much about why she married me.