Depending on the religion, there are many gods considered very powerful. For example, Lord Shiva is considered the most powerful god in Hinduism. He is known as the god of transformation and is widely revered both within and outside of India.
Other religions also have powerful deities. Allah is the supreme and most powerful god in Islam, considered the creator of the universe. In Christianity, God is believed to be all-powerful and omnipresent.
Ultimately, the concept of a "powerful" god varies across different faiths and belief systems.