Carob is known as a substitute for a cacao. Of course nice combination to chocolate. because of similar flavor these stuff.
Green tea biscotti: Greentea is Japanese style material. However green tea flavor and biscotti make a really good combination.
Buckwheat flour apple biscotti: Like buckwheat flour galette and cider is very good combination. They can say same situation backwheat flour's snack and apples combination is good.