What about Oracle Decks?

So being new, I was wondering about the difference between Tarot decks and Oracle Decks. And what are Oracle decks mainly used for? I am interested in them but know very little of what that are made up of, and used for.

Basically:
Any divination deck that isn't a Tarot deck, is usually deemed an Oracle.

Tarot decks have a structure of 78 cards. Oracle decks can have any number of cards.

Bee

Thank you Bee. )