A cool crossover idea in Naruto and Doraemon fanfiction is having Doraemon help Naruto learn about different cultures and technologies from the future. For example, Doraemon could show Naruto how advanced medical technology could heal even the most severe ninja injuries. And Naruto could introduce Doraemon to the concept of ninja skills and the importance of willpower in his world. This exchange of ideas could lead to some really unique adventures and storylines.
In Naruto and Doraemon fanfiction, a great crossover would be if Naruto's friends like Sasuke and Sakura were introduced to Doraemon's world. Sasuke might be intrigued by the scientific knowledge there and how it could enhance his power. Sakura, on the other hand, could learn about new ways of healing from Doraemon's gadgets. And the whole gang could go on adventures together, using both ninja techniques and Doraemon's amazing tools to face various challenges.