History says oil and fire. Naruto has wind. Jiraiya Ma/Pa toad combined fire, oil and wind to make a fire jutsu against pein called (deep fryer jutsu, or something like that.) Naruto could use oil/wind. If he's learned a basic fire technique then it's more flexible. Gamabunta used water bullets against Gaara as Shuukaku, so there's water too.
Either way the possible known combinations that are compatible with Naruto are wind, oil, water, and fire. Who contributes what is a separate question.