1. Flying Thunder God Technique: The Hiraishin no Jutsu allows instant teleportation to any marked location. It is undefendable and lost since the Second Hokage's death. 

2. Shadow Clone Technique: This forbidden technique creates solid clones of the user that can attack and think independently. However, it consumes a massive amount of chakra and is not taught in Konoha. 

3. Dead Demon Consuming Seal: The Shiki Fuujin allows the summoning of the Shinigami to seal a target's soul. Sadly, the user must sacrifice their own life force, leading to its loss after the Third and Fourth Hokage's deaths. 

4. Amaterasu: It is an S-rank fire release ninjutsu that creates unextinguishable black flames. It is forbidden due to its destructive nature and only known by a few Uchiha clan members. 

5. Izanami: This powerful genjutsu traps the victim in an eternal time loop of their own memories. It is forbidden as the user loses their eyesight and becomes blind.