There are three Great Fairies in Hyrule, and each one gives you a special reward if you answer their questions honestly and correctly. Below is a list of them, and how to get to each one.

Great Mayfly Fairy

Where to find her: Mt. Crenel, at the far right of one of the big wall areas. Drop a bomb to open a hole in the wall and access her fountain.

What she gives you: A bigger bomb bag

How to get it: Throw a bomb into the fountain and the Great Mayfly Fairy will appear. She will ask if you dropped the silver bomb, the golden bomb, or neither. Answer honestly: neither. In return for your honesty, she will increase the number of bombs that you can carry.

Great Butterfly Fairy

Where to find her: In the Minish Woods, reached by using the Cane of Pacci on a hole in the northeast area.

What she gives you: A bigger wallet

How to get it: Go up to the fountain and the Great Butterfly Fairy will appear. She will ask you do throw all of your rupees into the fountain. Do it, and she will say that she doesn't really need all of your rupees, and will reward your kindness with a bigger wallet.

Great Dragonfly Fairy

Where to find her: In the Royal Valley, behind a bombable wall near the entrance to the valley.

What she gives you: A bigger quiver

How to get it: Answer her questions correctly. She asks you five questions that you can figure out by going around Hyrule.

1. Did you find the fire element first: NO (it was the Earth element)
2. Is your grandfather's name Smee: NO (his name is Smith)
3. Does Melari have seven apprentices: YES
4. You used the Blabber nut to understand the Minish: NO (it was the Jabber nut, not the Blabber nut)
5. King Daltus's robe is white: NO (it's red)