Transuranium element
The applications of them are used far and wide, like how Uranium and Plutonium are used for fuel and weapons, Curium is used for rovers, Berkelium is used for creating other elements, notably Tennessine, and Americium being used for smoke detectors. Fermium to Lawrencium really don't have uses and after that, what scientists call superheavy elements are Rutherfordium to Oganesson, which also have no uses.