Gedou Mazou, also known as Heretical Demon Statue, is an extremely powerful summoning that is able to rival even the strongest tailed beasts. It is a gigantic demonic statue which is summoned first by Nagato during his battle against Hanzou and secondly by Uchiha Madara during the Third Great Ninja War. The statue can send out spectral dragons which steal the souls of those it touches. When Negato used it, the statue extended chakra rods which attached into his back and drained his chakra.
Enma is the powerful summon which the Third Hokage uses during his battle against Orochimaru. The summon can change his form from the King of Monkeys to a diamond-hard staff which the Third Hokage wields. Unlike many of the other summons, Enma appears intelligent and perceptive, conversing on equal terms with the Third during the battle and submitting to his authority when the situation appears dire. Although his abilities are not demonstrated in full during the battle, it is safe to assume that he possesses great power indeed, being the personal summon of Third Hokage, who is also known as the "God of Ninjas."
Manda is one of the most powerful summons demonstrated in "Naruto." The leader of the Snake Clan, he is originally the personal summon of Orochimaru and demonstrates his power on several occasions throughout the series, including in the fight between the three Sennins. Manda possess very fast movement, can tunnel through the Earth and can shed his skin when attacked. A second version of Manda is summoned later in the series by Kabuto and is said be larger, stronger and faster than the original.
Gamabunta is a giant toad, summoned successfully by the Fourth Hokage, Jiraiya, and finally Naruto. Gamabunta has been shown, in his fights against the Nine-tailed Fox Demon and Orochimaru's Manda, to possess great strength and stand firm in times of great peril. He wields a tanto, which is a small katana, and can also spit swirling balls of water to attack his enemies from a great distance. Aside from his great strength, Gamabunta has also shown himself to be intelligent, aware of his own limitations and perfectly capable of team work.