1. Sarutobi's Enma: Enma is the most powerful summoning animal in the early stages of Naruto. He can transform into a staff, becoming Sarutobi's weapon. However, he doesn't appear later on due to the Four-Tails's monkey, Son Goku, taking his place.
2. Sanjouyu, the Salamander: Orochimaru's summoning animal. It has highly poisonous abilities that even Orochimaru himself cannot resist, wearing a gas mask as a result. The depiction of the salamander in Naruto is not entirely accurate, but Orochimaru is still regarded as a demi-god and the one who granted the title of the Sannin.
3. Pain's Dogs: These immortal dogs are summoned by Pain, an adept in the Animal Path. They multiply as they fight and are invincible. To defeat them, one must either restrict their movements or kill Pain. Jiraiya had to use his toad stomach to defeat them in Amegakure.
4. Kurama, the Nine-Tails: Madara Uchiha used his Sharingan to control the Nine-Tails and summon it. During the battle with the First Hokage, it fought alongside Madara. After his defeat, the Nine-Tails were sealed inside the Uzumaki clan. It is one of the most powerful summoning animals.
5. Gedo Mazo: The shell of the Ten-Tails, known as Gedo Mazo, possesses formidable combat abilities despite lacking the chakra of the nine-tailed beasts. It was sealed on the moon, but Madara Uchiha summoned it into the ninja world when he awakened the Rinnegan.