During the time of Shivaji Maharaj, was Maharaja the only Hindu king in unbroken India or were there any other Hindu kings like Maharaja?

Not at all, the fiery brilliance of Shiv Chhatrapati breathed life into the dead issues in this country and again inspired Kshatradharma on this land of India. In this, many kings were encouraged to fight against the Mughals, some of whom were prominent

Maharana Rajasingh Sisodia (1652-1680) - The direct great-grandson of Maharana Pratapsingh, the Hindu Surya hero of Mewar, and a man of Shivaraya's own blood, who directly defied and trumpeted Aurangzeb's imposition of the jizya tax. Not only this, but after marrying Aurangzeb's wife, she defeated the Mughals 3 times. Where there was no one to give shelter to the idol of Krishna in Mathura, Maharana submitted and gladly took the responsibility of protecting the idol of Shri Krishna on his own shoulders and said that the Mughals would have to behead 1 lakh of my princes to touch this idol.

Ahom Kings - The kings of the Ahom dynasty of Assam, led by their commander Lachit Barphukan (Barphukan - Commander-in-Chief), like Shiv Chhatrapati, had driven the Mughals into their kingdoms with guerilla poetry.

Rani Chennamma (1677-1696) - This queen of the Keldi kingdom in Karnataka proved brave enough to fight the Mughal army to protect Chhatrapati Rajaram Maharaj on his way to Jinji.

Raja Chhatrasal Bundela (1671-1731) - After the Bundela Raja Champataraya was ungratefully killed by Aurangzeb despite helping him in his struggle for power against his brothers, his third son Chhatrasal came to the Deccan and after meeting Shiv Chhatrapati, became Veerashri Sancharli. Later he fought against the Mughals for a long time in Bundelkhand and established his own kingdom.

True Padshah Guru Gobindsingh (1675-1708) - After his father Guru Teg Bahadur was brutally killed by Aurangzeb, he held the post of Guru at the age of 9, but lost his 4 children and mother to the Mughals, together with his Khalsa Sikh followers, he fought the Mughals till his last breath.

Raja Ramsingh Jat (1670-1688) - This Jat king of Bharatpur, seeing Aurangzeb trapped in the south, directly attacked Fatehpur Sikri to avenge the destruction of the temples of Kashi and Mathura, broke Akbar's tomb and burned his remains, and was later killed by the Mughals.

Many small and big kings like him took part in the war against Aurangzeb and the Mughals and carved their name in golden letters in history.