How many forms of lord Vishnu?

Lord Vishnu is considered to have ten primary forms or avatars, known as the Dashavatara. These are:

Matsya (the fish)

Kurma (the tortoise)

Varaha (the boar)

Narasimha (the half-man, half-lion)

Vamana (the dwarf)

Parashurama (the warrior with an axe)

Rama (the prince and king of Ayodhya)

Krishna (the cowherd and prince of Mathura)

Buddha (the enlightened one, according to some traditions)

Kalki (the future avatar, who is yet to appear)

Apart from these ten forms, there are many other forms and manifestations of Lord Vishnu that are revered in Hinduism, such as Hayagriva, Narayana, and Mohini, among others.