By jumping out of a hole on a diagonal, you can get a reversed direction for Link. Although the animation for the reversed sprite is only shown when Link is facing downwards, Diagonal Angle Retention works on every facing direction. It is important to note that it only works on one diagonal per facing direction:
The angle can be maintained by holding said diagonal, or using an item that locks Link's facing position, such as the Sword, Shield, Gust Jar or Roc's Cape. Rolling also preserves the angle.
Using Diagonal Angle Retention and grabbing a pillar, it is possibly to pull them diagonally. This can be used in many places, but notably in Cave of Flames to skip the Big Key.
With Diagonal Angle Retention, we can use the Cane of Pacci on a hole, reenter it while preserving the angle and get a diagonal jump. This can be used in certain areas to get on a higher layer in unintential places, which will lead to out of bounds areas.