Hey, Infinity here. I have a theory on the whole Nature Transformation thing. I'm a hardcore Naruto fan and analyzer (kinda), and realized something unusual.
I understand that basic techniques shouldn't need a NT, like the Transformation, Shadow Clone, and simple chakra flow, but I think others should have, mainly between Yin and Yang.
First of all, Ino's Mind Transfer. I feel like that should be Yin, since it transfers her own spirit across to another person through Ninjutsu.
Second of all, Medical Ninjutsu. I feel like when there is visible chakra out of the body used in a technique of no other NT, it should be Yang since it represents physical. And most Medical Ninjutsu has physical chakra shown and/or shared (not saying the basic Chakra Transfer should be Yang). And not only that, but it physically heals the body.
Third, Konohamaru's Yang seal technique. It has Yang in its name and makes a physical seal of chakra, so I feel like this meets the Yang requirements, same with his green triangle seal Jutsu since those physically seal targets.
Fourth, Tayuya's Revolt of the Demon World. She commonly uses Yin Genjutsu, and this move is said to use spiritual energy, so, this one should be obvious.
Fifth, Tsunade and Sakura's strength-enhancing and healing seal Jutsu since those physically affect the body's strength and regeneration if I recall correctly.
Those were just examples. I'm not saying that every technique should be classified, but some that obviously require classification should have that, just saying.