There are very many different ninja arts one can study and heres a list of them!
Ninjutsu (忍術; Literally meaning "Ninja Techniques"), is a term referring to almost any technique which allows the user to do something that they otherwise would be incapable of doing, including the usage of weapons. Unlike genjutsu, which makes the opponent see illusions, the effects of ninjutsu are real. They vary greatly in purpose, with the simpler ninjutsu serving such tasks as transforming the user or allowing them to evade attacks. These techniques are often second-nature for experienced shinobi, who can use them at will. More complex ninjutsu manipulate one's surroundings or utilise the elements, respectively serving such tasks as healing others or manipulating nature transformations.
Ninjutsu, most of the time, relies on chakra and hand seals to be effective. The hands are put in sequential positions that moulds and manipulates chakra in the necessary manner to perform a technique. This is not always needed, however, and some techniques become second nature to experienced ninja, after which they can perform them at will.
Genjutsu (幻術; Literally meaning "Illusionary Techniques") are techniques that are employed in the same fashion as ninjutsu, requiring chakra and hand seals. However, the primary difference between the two is that the effects of genjutsu are illusory; instead of attacking the victim's body, like taijutsu or ninjutsu, genjutsu techniques manipulate the flow of chakra in the victim's brain, thus causing a disruption in their senses. According to the Second Mizukage, genjutsu fittingly falls under the broad category of Yin Release.
This is frequently used to create false images or to cause pain from trauma (because the body is led to believe it is in pain); however, there are plenty of other uses depending on the situation
Taijutsu (体術; Literally meaning "Body Techniques") is a basic form of techniques and refers to any techniques involving the martial arts or the optimisation of natural human abilities. Taijutsu is executed by directly accessing the user's physical and mental energies, relying on the stamina and strength gained through training. It typically does not require chakra, though chakra may be used to enhance its techniques. Taijutsu generally requires no hand seals to perform, occasionally making use of certain stances or poses, and are far quicker to use than ninjutsu or genjutsu. Taijutsu is simply put: hand-to-hand combat.
Medical Ninjutsu (医療忍術, Iryō Ninjutsu; Literally meaning "Medical Ninja Techniques") is a branch of ninjutsu associated with healing, as well as the manipulation of their own, or anothers' body, practised by shinobi categorised as "medical-nin". The use of medical ninjutsu requires very advanced chakra control, as well as extensive knowledge on such things as herbs, medicines, the human body and even poisons.
Fūinjutsu (封印術; Literally meaning "Sealing Techniques") are a type of jutsu that seal objects, living beings, chakra, along with a wide variety of other things within another object. Fūinjutsu can also be used to unseal objects either from within something or someone.
The Puppet Technique is a unique ninjutsu fighting style; this technique uses chakra threads to control puppets like marionettes. Any number of chakra threads can be used to control a puppet, but users with more skill can use fewer strings per puppet. Both Chiyo and Sasori demonstrated the ability to control entire puppets perfectly using just one thread. While most puppeteers (傀儡使い, kugutsutsukai) would normally be able to control ten puppets at most (one per finger), Sasori's self-modification allowed him to control up to one hundred puppets at a time.
A sensor type (感知タイプ, kanchi taipu; Literally meaning "Perception type") is ninja that is capable of detecting the presence of other people through their chakra.
Kenjutsu (剣術; Literally meaning "Sword Technique") pertains to techniques that entail the use of swords, whether the users be shinobi, or samurai. Kenjutsu can be used in combination with taijutsu, ninjutsu, chakra flow and even genjutsu in order to achieve more devastating techniques