What are the most unique jutsus and abilities?

[Umari Senju]

yes he used water gun tech on gaara and streaming danger tyranny on alliance

I think the OP meant Hydrafication tech. Which I think he had. Didn't he get his head chopped off only to have it turn to water? or am I thinking of Suigetsu here?

 

[Moe22]

Sai's super beast scroll

 

[DaileyM]

Definitely Konan, Its exclusive to her only.

 

[vasu 32]

Obito~Kamui [this shit is broken],no contest.

 

[kimb]

Hidans immortality, Kimimaru's bones, Sai's scrolls

 

[Kronnic]

2nd Hokage's paper bombs that summons other bombs.. This has a possibility to be infinite.