1. Flip Effect Monsters: These are monsters with the "Flip" effect. They start in face-down Defense Position and are flipped face-up by certain effects or triggers. This is the most common type of "flip down" card.
Here are some examples of Flip Effect Monsters:
* "Mystical Space Typhoon" (a Spell card that lets you destroy a Spell/Trap card on the field) can be used to flip a face-down Flip Effect Monster face-up.
* "Sangan" (a Flip Effect Monster that can special summon other monsters from your deck) flips face-up when it's attacked.
* "Morphing Jar" (a Flip Effect Monster that can swap the monsters on the field) flips face-up when it's destroyed.
2. Trap Cards: Trap cards are set face-down and remain that way until their effect is activated, which can be triggered by a certain condition. When a Trap card is activated, it is flipped face-up.
Here are some examples of Trap cards that can be "flipped down":
* "Torrential Tribute" (a Trap card that destroys all monsters on the field) is flipped face-up and activated by its trigger condition.
* "Mirror Force" (a Trap card that destroys all attacking monsters) is flipped face-up and activated by its trigger condition.
It's important to note that some cards may have effects that involve flipping cards face-down, but this doesn't necessarily fall under the category of "flip down." For example, "Dark Hole" destroys all monsters on the field, regardless of whether they're face-up or face-down.
If you have any further questions about specific cards or their effects, feel free to ask!