The effects vary, but are incredibly powerful and include changing your hand, forcing your opponent to switch their active Pokmon, discarding your opponent's Energy, and more
Vault of Champions has a collector number of 360/361, and Verhey confirmed that the set has 361 cards, meaning that there is only one card after it in the set
Reave Soul actually saw a decent amount of play early in the current Standard because it kills Mantis Rider, Warden of the First Tree, and Jace, but Grasp one-ups that and adds Anafenza to the list
Getting around pesky indestructible effects, whilst also helping you along if you have anything at all that cares about people sacrificing their stuff, its not difficult to see why this colorless sorcery made it so far up the list