Hats
Bull Wario
Ground Pound, then start climbing a ladder, but release all buttons before the shaking ends. Wario will reset to standing state.
Ground Pound, hold Forward and tap B to Bull Charge. Make sure you're still holding Forward when the shaking ends, and Wario will reset to walking state, but is unable to Bull Charge. Walk into an enemy and you'll Bull Charge automatically.
Hold up while breaking a block from the bottom side and you'll hear the *cling* from attaching your horns in the ceiling, but the block will break and you'll fall down.

Jet Wario
Jump slightly and then fly. You'll be able to fly 1/4 through the ceiling. Jump just out of the water and fly. You'll fly at full speed, even though Wario is still for a large part in the water. You can combine these two things in Course 9, third room: jump just out of the water and fly at full speed under the wall while being underwater! Takes some practice to time it right.
When flying, before enter Landing state, quickly tap B twice. When timed correctly, you won't lose altitude and can fly arbitrary distances.
Hold up while pressing B to stop a flight exactly at a portal. You'll continue to hear the flight sound, even though you're not flying anymore.

While flying, press Backward and B simultaneously and you'll enter landing mode.
Dragon Wario
Dragon Wario's flame gets watery based on whether wario is in swimming mode, not based on whether the flame is in the water.
