Morgana le Fay

See 'Only It Can Cast' in the codex.

Her hand of cards continues to exist in its own zone, though Morgana can no longer cast those spells without the Spellcaster ability. Since you control Morgana, you can still look at the cards.

Your opponent will be able to have Morgana cast the spells in her hand, assuming they have the mana and appropriate threshold. You can't look at the cards in her hand while you don't control her. Remember that cards always return to their owner's cemetery, hand, or decks when leaving the realm after being played from Morgana's hand, regardless of who controls her.

If Morgana is transformed, the ongoing effect which created her hand of cards will continue to apply, and the hand will continue to exist. If Morgana's new form does not have the ability to cast spells, she will not be able to cast them, but if she becomes a spellcaster again she will still have access to her hand.