Hinduism is supposed to be 'apauruseya', i.e., of impersonal origin & so also are the Gods of Hinduism. They are eternal & though the deities appear to be different & independent, they are really facets of the same Brahman, the Supreme God.
As Sri Ramakrishna says, there can be as many spiritual paths as there are spiritual aspirants & similarly there can really be as many Gods as there are devotees to suit the moods, feelings, emotions & social background of the devotees.
The Hindu scriptures were eloquent while describing the qualities of God. He is all-knowing & all powerful. He is the very personification of justice, love & beauty. He is ever ready to shower His grace, mercy & blessings on His creation.
From the Rig Veda, we come to know of the vedic gods eight Vasus, eleven Rudras, twelve Adityas, Indra & Prajapathi, being the Gods of earth, the heavens & the space.

The main Hindu Gods as we accept today can be broadly classified as Saiva Gods (Siva, His consort, His sons, His other forms ), Vaishnava Gods ( Vishnu, His consort, His various avatharams ) & Sakthi (Personifying all energy).
The Vedic Gods
Brahma - The God of Creation
Vishnu - The God of Maintenance
Dasavataram
Matsyavataram ( Form of a fish )
Kurmavataram ( Form of a tortoise )
Varahavataram ( Form of a boar )
Narasimhavataram ( Form of a lion headed man )
Vamanavataram ( Form of a dwarf )
Parasuramavataram
Ramavataram
Balaramavataram
Krishnavataram
Kalkiavataram ( yet to come )
Siva - The God of Destruction
Saraswathi - Consort of Lord Brahma
Lakshmi - Consort of Lord Vishnu
Parvathi - Consort of Lord Shiva
Ganesha - Son of Shiva & Parvathi
Navagrahams
Surya Bhagavan
Chandra Bhagavan
Chevvai Bhagavan
Buda Bhagavan
Guru Bhagavan
Sukra Bhagavan
Sani Bhagavan
Rahu Bhagavan
Kethu Bhagavan
Stories on Lord Ganesha
Story of Gajamugasuran
Story of Agasthyar - Cauvery
Story of Ravana - Aathma Lingam
Vinayagar wrote the Bharatham
Rudraksham