1. Fire Release: Great Fireball Technique. The Great Fireball Technique is a widely known ninjutsu in the Uchiha clan. However, it has never been shown to be effective in killing anyone in the anime. This technique is considered quite disappointing due to its lack of impact.

2. Amaterasu. Amaterasu is a powerful genjutsu activated by Sasuke and Itachi's Mangekyou Sharingan. It summons everlasting black flames. Unfortunately, it has also never been demonstrated to kill anyone. There are various ways to counter it, such as using tailed beasts' chakra or severing limbs, making it less effective.

3.

Reverse Four Symbols Sealing. Reverse Four Symbols Sealing is a forbidden jutsu employed by Danzo Shimura. Despite his attempt to use it against Sasuke and Tobi, he ended up taking his own life. This technique proved to be useless and exposed Danzo's vulnerability to Sasuke, even with the aid of Izanagi. 

4. Body Flicker Technique. The Body Flicker Technique is a jutsu used by the Third Hokage and Kakashi Hatake. It creates the illusion of decapitation by burying the opponent underground, leaving only their head visible. Nevertheless, it lacks practical use in combat situations.

5. Corpse Kiss.  Corpse Kiss is a ninjutsu employed by Grave Robber No Wind, allowing them to absorb an individual's chakra through a kiss. However, it failed when No Wind attempted to kiss Naruto's shadow clone, rendering the technique almost useless.