Hello @eeveejolteon very warm welcome to the forums, very good to have you here. It is awesome to see younger collectors like your nephew getting the older ones back into the hobby. I am sure collection with him will be an amazing experience for both of you. This is a great place to be with lots of information available to read and also lots of friendly people who can help you with your collection goals.
Just to get your started, you can use this amazing and informative article by @Quuador to get you started on all possible combinations.
You can also refer this and this threads as inspiration for others who are working on pokedex binders.
Welcome again and I look forward to hearing from you more and your journey with your collection.
Cheers!