Kamiki Sun Fragment Early
It is possible to use Slope Storage to reach the Sun Fragment chest in Kamiki village early. You're intended to reach the chest after the Water Lily tutorial, and it cannot be jumped to from the shore near Susano's house. By storing a nearby steep slope, the resulting vertical boost can be used to start an Air Ground Tackle over the invisible walls surrounding the shore, making it possible to reach the chest. See https://youtu.be/aWHILu9_VlI.
Sun Fragments aren't useful or required in any standard category, so this trick is useless.