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.

Genjutsu: Mangekyō Sharingan
A variation of the technique, utilised with the use of a Mangekyō Sharingan. By establishing direct eye contact with the intended individual, the user can lock people within a genjutsu of their choosing in order to achieve various effects such as forcefully extracting information that the victim possess, immobilising a opponent or to carry out a mission. Practitioners of such a variation include Itachi, Madara and Sasuke Uchiha.

Genjutsu: Rinnegan
Using their Rinnegan, the user 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 a loss of consciousness. The only known user of such a variation is Sasuke Uchiha.

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.
 * 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.