Most of these items no longer exist, as all Ancient Magic Crystals of the Sun were removed in the 'Great Crystal Purge', Fruit of the Sun was merged into Fruit of Nature and the same for Essence of the Sun and Essence of Nature, and all the sun processing stones were merged into general-purpose processing stones. The seal, while still around as far as I know, is a quest item that can't be recovered if you got rid of it after completing the quest.

That leaves only the belt. However, there's no point in making the belt, because one of its materials - Golden Sun Coral - works as well!