Well, faeries in general are creatures of long standing folk tradition, mainly of European cultures but also sighted by other cultures around the world. The fae include not only the cute, feminine winged creatures that you may be familiar with (a la Disney), but many magical creatures associated with the woods and waters of the older worlds. Their land, faerieland, is on a plain which both inhabits ours and is beyond ours. There are a great variety of fae, much too numerous to count. And, despite the popular misconception that these creatures are all cute and nice, there are many stories of mischievous acts by the fae (for instance, stepping into the fairy shoes can cause you to dance to death, at their delight). They are capricious, not locked into the Christian conceptions of "right" and "wrong". In fact, they are sometimes linked with mythic tradition of Lillith, the first woman before Eve, an equal to Adam, who clashed with him and was relegated to a different realm, and thus the fae are her offspring.
In regards to Faery Oracle decks, rostie linked you to the two major decks which are non-tarot. Brian Froud & Jessica Macbeth's Faeries' Oracle is what we are studying here. Link to
www.faeries.net to see much of Froud's work and find a link to the Faeries' Oracle. The deck is a creation of Froud and Macbeth, and thus isn't tarot. It works as most any other deck, and what I love about it is that it encourages you to use your intuition. There are meanings for the different fae, but the book encourages you to find your own meanings for the cards, and even for spreads they give you. The cards are stunning.
The other major oracle deck is Anna Franklin and Paul Mason's Fairy Ring Oracle. This deck has four suits corresponding to the four seasons, with numbered and court cards in each suit, plus it has eight festival cards corresponding to the eight fairy festivals. The fairies depicted are traditional Celtic fairies. Franklin is a Wiccan High Priestess and brings great knowledge and understanding to the cards. She offers meditative advice as well as reading meanings, but even she cautions not to meditate on certain fae, which could be quite dangerous. Many people have been turned off by this deck, but I think it is wonderful.
I hope some of this info was helpful
