Sickle and chain (kusarigama): Used to entangle the opponent’s sword or spear or body and then attacking with the sharp blade.
Grappling hook (kaginawa): Commonly used by not only ninja but also the samurai during the sieges of Japanese castles at night.
Throwing stars (shuriken): Usually used by placing on the ground or throwing in a different direction to distract the opponent. Sometimes poison is put on the edges of the shuriken.
Ninja Sword (a.k.a. Ninjato, Shinobikatana, Chokuto). Short, single edged straight sword. The scabbard tends to be long to hide things like poison and the hand grip is relatively larger. The cover can be used to breath under the water or listen to the people talking in the next room.