There's only really 4 Amulets that are important, and can be acquired easily:
Niku-wan, Rinkamo, Awanko (the 3 best multiplier slowdown amulets), and Sugamo-chan (Voltage Booster)
They make the game much easier, and you can pretty much skip every other amulet. They were the only 4 amulets I had when S Ranking Hyper Mode multiple times.
EDIT: TweenDoriru beat me to it. XD