What a great idea to have a photo book. I remember him saying he feels uncomfortable looking at too many pictures or fanarts of himself, so I think he would be more interested in knowing who his individual fans are and how our lives have been impacted by him in very different ways.
And I support the idea of including a small inexpensive gift he could wear or keep with him. It could be a simple engraved bracelet or a personalised tee or luggage tag