They are all found inside various enemies and can be retrieved by Bowser using the Vacuum Block and sucked the Blitty out of the enemy. If fifteen Blitties are found, Broque will let Bowser give Broggy a walk, gaining you the special move Broggy Bonker.
Blitties can be found in the following enemies;
- Chain Chawful
- Sniffle Thwomp
- Dark Trashure
- Dark Mechawful