Figgy Fizz

Figgy Fizz is Bert's favorite soda. Bert has a Figgy Fizz cap in his bottle cap collection.

The soda has been mentioned in several Sesame Street books:

The Sesame Street Dictionary (1980) - One picture features Sully dropping a bottle from atop a construction site when Biff asks for it, and another features a small factory assembly line.
Big Bird Brings Spring to Sesame Street (1985)
Big Bird Can Share (1985)
Just Like Ernie (1988)
My Name Is Bert (1991)