Genjutsu: Sharingan

This is simply the generic use of genjutsu as employed by Sharingan wielders. By establishing direct eye contact with the intended opponents, the user can lock them within a genjutsu of their choosing in order to achieve various effects. These effects range from inducing instantaneous, but temporary, unconsciousness in an opponent, to forcefully extract any valuable information that they possess  controlling their actions,  undo genjutsu, or to show memories.

Variants

 * Using his Sharingan, Sasuke stares at his opponent directly in the eyes and they stare back. Then a shadowy figure of himself appears before them, forcing them under a genjutsu. An image resembling his Susanoo appears in front of the opponent and grasps them as it begins "assimilating" them into itself. This breaks the opponent's will. Afterwards, the opponent is left incapacitated.
 * Itachi is seen using an illusion that traps the victim in a dark empty space where their body is made of paper that burns from toe to head while the user is watching. The genjutsu will make it harder for the target to move properly. It bears a great resemblance to his Tsukuyomi, though it is used with the regular Sharingan.
 * Madara's Sharingan could control a tailed beast, while Obito's could also control a jinchūriki, with his eye power being compared to Kotoamatsukami.
 * Kakashi could use the Sharingan to hypnotise the target, making them make seals at the same time as he did, thus giving the illusion he could see into the future. He was also able to put multiple people to sleep with a single glance with his Sharingan, even shinobi of Anbu calibre.
 * Shisui was able to render people unconscious with a single glance with his Sharingan.

Mangekyō Sharingan variant
Due to it being a higher form of the Sharingan, the Mangekyō Sharingan can also be used to cast this technique, while some users have seemingly required to activate their Mangekyō Sharingan to cast genjutsu. The effects from the genjutsu range from immobilising a opponent to giving orders to carry out a mission. Its use can cause pain to the user, and in the anime, the casters Mangekyō Sharingan can also appear over the target's eyes.

Rinnegan variant
With the Rinnegan, Sasuke is able to cast a genjutsu strong enough to take control of the nine tailed beasts simultaneously. Hagoromo Ōtsutsuki stated that Sasuke can use this technique through a single glance. Unlike other genjutsu, this technique apparently does not subdue the mind of the victim. It can also be used to cast the illusion of an attack onto a victim, resulting in its collapse and loss of consciousness.

Trivia

 * Sasuke's completed version of Susanoo was first seen in this genjutsu, though as a shadowy figure before its complete début in the fight against Danzō.
 * Killer B noted that genjutsu is generally useless against perfect jinchūriki and Gyūki was able to release this technique when it was cast on him.
 * By making eye contact with Kurama's jinchūriki, Obito could use this technique to control the tailed beast.
 * In the anime, Madara had to deactivate his Rinnegan to his Eternal Mangekyō Sharingan to use this technique.
 * Despite genjustu working by altering the chakra flow of a target's cerebral nervous system, this technique effected Mecha-Naruto who doesn't have a brain.