List of Hindu deities

Hinduism is the largest religion in the Indian subcontinent and third largest religion in the world. It comprises five major sects or denominations, Vaishnavism, Shaivism, Shaktism, Ganapatism, and Saurism whose followers consider Vishnu, Shiva, Shakti (Devi), Ganesha, and Surya to be the Supreme deity respectively. Smartism sect considers all the above five deities as equal. Most of the other deities were either related to them or different forms (incarnations) of these deities. Hinduism has been called the "oldest religion" in the world, and many practitioners refer to Hinduism as "the eternal law". (""). Given below is a list of the chief Hindu deities followed by a list of minor Hindu deities (including demi-gods).
Smartism, an older tradition and later reestablished by Jagatguru Adi Shankaracharya, invites the worship of more than one god including Shiva, Vishnu, Brahma, Shakti and
Ganesha (the elephant faced god) among other gods and goddesses. It is not as overtly sectarian as either Vashnavism,
Brahmanism or Shivaism and is based on the recognition that Brahman (God) is the highest principle in the universe and pervades all of existence.
Main deities.
The Hindu trinity, also known are tridev consists of Brahma the Creator, Vishnu the Preserver, and Shiva the Destroyer and reincarnator. Their feminine counterparts are Saraswati, the wife of Brahma, Lakshmi, the wife of Vishnu, and Parvati the wife of Shiva. The followers of the last two form two major sects.
Brahma.
According to Hinduism, Brahma is the creator of the entire cosmic universe. Although he is the creator, he is hardly worshipped in modern Hinduism. He is identified with supreme vedic god, Prajapati. He married Saraswati, who emerged to give knowledge to create.
Some alternative names for Brahma are 
Devi (goddess).
Communities of goddess worship are ancient in India. In the Rigveda, the most prominent goddess is Ushas, the goddess of dawn. In modern Hinduism, goddesses are widely revered. Shaktism is one of the major sects of Hinduism. Followers of Shaktism believe that the goddess (Devi) is the power (Shakti) that underlies the female principle, and that Devi is the supreme being, one and the same with Para Brahman. Shakti has many forms/manifestations like Parvati, Durga, and others but there are also goddesses that are parts of Shakti such as Lakshmi and Saraswati. Devi is believed to manifest in peaceful forms, such as Parvati the consort of Shiva and also in fierce forms, such as Kali and Durga. In Shaktism, Adi Parashakti is regarded as Ultimate Godhead or Para Brahman. She is formless i.e. Nirguna in reality, but may take many forms i.e. Saguna. Durga and Lalita Tripurasundari are regarded as the Supreme goddess in the Kalikula and Srikula systems respectively. Shaktism is closely related with Tantric Hinduism, which teaches rituals and practices for purification of the mind and body. Some different parts of Shakti (Devi) the Mother Goddess:
Shiva.
Shaivism is one of the major Hindu sects. Adherents of Shaivism believe that the god Shiva is the supreme being. Shiva is the destroyer god among the Trimurti, and so is sometimes depicted as the fierce god Bhairava. Shaivists are more attracted to asceticism than adherents of other Hindu sects, and may be found wandering with ashen faces performing self-purification rituals.
Some alternative forms of Shiva (and Bhairavs) are listed below:
Vishnu.
Vaishnavism is the sect within Hinduism that worships Vishnu, the preserver god of the Hindu "Trimurti" (the Trinity), and his many incarnations. Vaishnavites regard him to be eternal and the strongest and supreme God . It is a devotional sect, and followers worship many deities, including Rama and Krishna both the 7th & the 8th incarnations of Vishnu respectively. The adherents of this sect are generally non-ascetic, monastic and devoted to meditative practice and ecstatic chanting. Some alternate names of Vishnu the Preserver:
Avatars (incarnations).
Lakshmi.
Ashta Lakshmi.
Additional Forms
In some Ashta Lakshmi lists, other forms of Lakshmi are included,
Rigvedic deities.
The Rigveda speaks of Thirty-three gods called the Trayastrinshata ('Three plus thirty'). They consists of the 12 Adityas, the 8 Vasus, the 11 Rudras and the 2 Ashvins. Indra also called Śakra, lord of the gods, is the first of the 33 followed by Agni. Some of these brother gods were invoked in pairs such as Indra-Agni, Mitra-Varuna and Soma-Rudra.
Rudras.
The "Ramayana" tells they are eleven of the 33 children of the sage Kashyapa and his wife Aditi, along with the 12 Adityas, 8 Vasus and 2 Ashvins, constituting the Thirty-three gods. The "Vamana Purana" describes the Rudras as the sons of Kashyapa and Aditi. The "Matsya Purana" notes that Surabhi – the mother of all cows and the "cow of plenty" – was the consort of Brahma and their union produced the eleven Rudras. Here they are named: Nirriti, Shambhu, Aparajita Mrigavyadha, Kapardi, Dahana, Khara, Ahirabradhya, Kapali, Pingala and Senani. Brahma allotted to the Rudras the eleven positions of the heart and the five sensory organs, the five organs of action and the mind.
Vasus.
Assistants of Indra and of Vishnu
Ashvins.
The Ashvins (also called the Nāsatyas) were twin gods. Nasatya is also the name of one twin, while the other is called Dasra.
Number of deities in Hinduism.
Most of the Hindu temples are dedicated to Shiva, Vishnu (including his incarnations Krishna and Rama), Brahma, Shakti (the mother goddess, hence including the forms of Durga and Kali and the goddesses Lakshmi and Saraswati), Ganesh and Hanuman. The Hindu scriptures claimed that there were 3 "Koti" or 3 crore gods, "koti," in Sanskrit, means "crore" (3 कोटि = 10 prakar, tarah ). Crore also translates to 10,000,000 or 10 million. 
One theory is that the number 3 crore (30 million) gods refers to the total count of all living beings in nature signifying that god exists in every living being. This is in line with the belief of Indians to respect all living beings as gods. It is estimated that the world population was around this number about a 1000 years ago when this number would have originated. It also explains the many gods (e.g. the grama devatas or village gods who were clearly living persons at one time and many of the other gods who were believed to have been persons, e.g. Rama and Krishna).
Another theory is that the number might be figurative but there are several names and forms for the multitude of gods.