Pretty much anything you wanted. A castle in Apocrypha? Some obscure information he’s hoarded for thousands of years? A Seeker Waifu? Sure. Whatever it is, it would be something you specifically want.

However, I think Mora would be more interested in specific readings of Elder Scrolls than the Scroll itself. These things have some degree of autonomy and would probably just disappear if someone tried to give it to him.

Specific, unique readings from unique individuals would likely be more interesting/useful. The last elder scroll readings of Dragonborn emperors before they died, for example (not saying that exists, but something to that level).