In My Hero Academia, heroes are defined by their actions, not the brute strength associated with their powers (or quirks, as the show calls them). While the main characters typically exhibit the more incredible abilities, underrated skills tend to get lost in the shuffle. Many of these quirks are more useful than visually impressive.
Edgeshot's Foldabody allows him to make his body so sharp that it can cut like a sword, or so thin that he can slip through cracks, all at the speed of sound. While it's easy to see why this quirk is incredible, Edgeshot himself is pretty forgettable. Other underrated quirks have uses that may not seem immediately obvious – Shoji Mezo's Dupli-Arms can do a whole lot more than hold four coffee mugs at once.