By performing Boss Door Clipping, it is possible to clip past a boss door, which means entering the next room without triggering the transition.
Since the transition isn't triggered, no actors, walls, cutscenes etc. are loaded on the other screen, meaning Link can freely walk around. The loading zones, however, are always loaded.
Using this, it is possible to trigger loading zones on any side, allowing for some pretty interesting skips.
How to:
To perform Boss Door Clipping, you will either need the Lantern or the Magical Boomerang.
Lantern:
Equip the Lantern on the B button and position yourself in front of a boss door
Turn on the Lantern and press A or R immediately afterwards to open the boss door
If done correctly, Link will slide through the loading zone without triggering it
Magical Boomerang:
Equip the Magical Boomerang on any button and position yourself in front of a boss door
Throw the Magical Boomerang away from the boss door
Open the boss door and start holding down the button the Magical Boomerang is on
Continue holding down the button until Link got past the loading zone
After clipping, you will not be able to go back up and walking downwards too far will trigger and load the correct screen.
Keep in mind that it is very easy to softlock when going to another screen, since there is a high chance you will spawn inside a wall or even out of bounds.
Uses:
Early blue warp room in Temple of Droplets
Skipping the 2nd half in Palace of Winds