Black Fairy Speculation:

[YutG]

I wonder if the Black Fairy has any kind of Magic of her own. I think she is using Gideon as a battery

Is it possible that by giving Birth to Rumple she lost her magic?

Reasons:
the other Fairies are nuns. The other fairy's relationship with Grumpy was discourage.
She hasn't shown any offensive capabilities without Gideon Nearby.
She evaded Black fairy dust when it supposedly came from her when Gideon tried to use it on her.