There are some dragons Team Umizoomi met, mostly in Season three.
Season One Dragon
Milli, Geo, and Bot help their friend Jeannie find all the missing shaped pieces to her dragon kite. It was only shown in the first episode: The Kite Festival.
Season Two Dragons
The Girl Dragon
The Toy Dragon
He was seen in Umi Toy Store, where he blocked Sir Geo's path in The Knights in Shining Armor Boardgame. He would move unless Geo could get his favorite snack, which was the pepperoni pizza.
Season Three Dragons
These dragons come from the very special episode: Let's Play Math Dragons!
The Math Dragons
They are three young math dragons, one female and two males. The female is a Shape Dragon and the males are a Pattern Dragon and a Number Dragon. They hatched from their eggs.
The Chomping Dragons
They chomp a lot mostly to show what shape they want to eat. The number of times chomped and munched indicates the number of sides of the shape they want to eat.
The Flying Dragons
There are two different kinds: Up and Down Dragons. The Up Dragons are different from the Down Dragons.
The Big Dragon
Out of all the dragons, he is the biggest and strongest. He's got big feet that can stomp anything flat and a strong tail that can smash anything. He also has a saddle on his back that looks similarly like Yoshi from the Super Mario Series (particularly Super Mario World).
The Baby Math Dragons
As of the conclusion after finding all three dragon eggs, they hatched successfully with three cute baby dragons. Here they are: Shape dragon (yellow female), Pattern Dragon (green male), Number Dragon (purple male).
The Stinky Dragon
The main antagonist dragon. His name says it all because he is really stinky. Team Umizoomi encountered him in the passageways to all three levels. Everytime they get away from him and close the exit door, he says "That Stinks!" and then walks away unhappily.
Season Four Dragons
The Dragon Skateboard
It was just a picture of the dragon skateboard with four orange wheels belonging to Logan in The Boy with the Dragon Skateboard. The team must find the missing pieces to Logan's dragon skateboard when some bad guys called The Troublemakers as their first appearance destroy it.
Raining Dragon Flowers
Grog is still not giving up so easily. It is also shown in The Sunshine Fairy. He pulls out a bell and rings it, which wakes up the Dragon Flowers. The team finds out that these flowers are called Dragon Flowers because they breathe fire. Milli changes the pattern on her dress to make a water drop pattern. The pattern of water drops puts out the fires in the Dragon Flowers and puts them back to sleep. The little water drops put out the little Dragon Flower, and the big water drops put out the big Dragon Flowers. Soon, Milli puts all of the Dragon Flowers back to sleep.
Max The Dragon
Milli, Geo, and Bot are Umi Knights who must save the kingdom by helping Max the dragon find his glasses because Max is blurry without them.