Transformation

Mumbo's Mountain

 * Termite

Treasure Trove Cove
None

Clanker's Cavern
None

Bubble Gloop Swamp

 * Crocodile

Freezeezy Peak

 * Walrus

Gobi's Desert
None

Mad Monster Mansion

 * Pumpkin

Rusty Bucket Bay
None

Click Clock Wood

 * Bee

Transformation

 * Dragon

Spell

 * Heal

Transformation

 * Stony

Spell

 * Summon

Transformation

 * Detonator

Spell

 * Levitate

Transformation

 * Van

Spell

 * Power

Transformation

 * Submarine

Spell

 * Oxygenate Water

Transformation

 * T-Rex (Two sizes)

Spell

 * Enlarge
 * Shrink

Transformation

 * Washing Machine

Spell

 * EMP (Electro Magnetic Pulse)

Transformation

 * Snowball

Spell

 * Life Force

Transformation

 * Bee

Spell

 * Rain Dance

Banjo-Kazooie: Grunty's Revenge
(Note: Since the same transformations are available in all of the different worlds, there is no specific world categorization.)
 * Mouse
 * Candle
 * Octopus
 * Tank