Driftstone: Great for building in the air and parkour creations

Driftstone can be found in The End; specifically, in high altitudes in Small End Islands biome. Driftstone generates in small star-like chunks and appears purple and translucent. When mined, you get the driftstone, which can be placed in midair roughly 3 blocks away from you. This would help builders who want to build in the air, as they wouldn't have to build blocks all the way up to that height.

One ambitious concept though, is that driftstone can start moving in a cardinal direction when powered by redstone. When it is powered, the side of the block it was powered on is the direction the block will move away from. This wouldn't make flying machines completely obsolete though, as it will stop moving when it has moved 64 blocks away from its starting position, or when it hits a wall. This block would be amazing for parkour challenges as redstone can activate these blocks to move back and forth and players would have to jump from one to another to get across a gap.