For instance, the Deal with the Devil. In tales, the Devil has to come through. Even if you fulfilled your side only technically. In the witch trials, the accepted line was that he would promise you the moon to get you into the pact, and jeer at you afterwards: of course, you won't get riches and power, here's some magic powder to get revenge.
Or actual fairies. The précieuses of course had courtiers with magic powers and just called them fairies, but even in more folk-dervied tales, Rumpelstiltskin and his ilk are vulnerable only to their true names, not to iron or church bells or all the rest.
Get fun when you draw on both for a tale.