Classic Balloon Corporation manufactured a nice line of Sandra Boynton mylar balloons.
Sadly, only a few of these balloons are still available.

The Happy Birthday balloon with the cat and confetti and 'Have an Udderly Cool Birthday' are still available from The Balloonery in Stockton, CA.
The cat balloon is here.
The cow balloon is here.
They don't have the cow balloon advertised as a Boynton, so searching for "Boynton" won't find this one.

'Happy Birthday to Yoooo' and 'You're Outstanding in the Field' are still available from Cow Depot.
You can find them here. They are a little way down the page, at the start of the balloon section.

Many thanks to Illona Bobritsky for finding the cow balloons and letting me know about them!

You may note there are gaps in the array. These are placeholders for coming attractions - balloons that I know about but don't have pictures of yet.

Celebrate! Congratulations! Congratulations!
Congratulations on your tremendous feat! Tyrannosaurus Rx Get well immediately!
Get well soooooon! Go For It! Goodbye and Good Luck
Grin and Ignore It Hang In There! Ha-ppy Birth-day to yoooo!
Happy Birthday! Happy Birthday! Happy Birthday! Indulge!
Welcome to the Middle Ages Happy Birthday to a terrific kid! Barnyard Dance
Happy Easter Happy Easter! You Lucky Duck
Happy Valentine's Day Have an udderly cool birthday! Hope You're On Your Feet Again Soon
Hope You're On Your Feet Again Soon I Love Grandma I Love You!
Love You Valentine Love You Love You
MOM Simply the best. Smile! Wishing You a Happy Birthday!
You are simply the best! You're one in a million! You're outstanding in the field



Sandra Boynton