Different religions, dogmas, concepts, creed are accepted and followed in the world. Concerning Creator of all universes/worlds, all living and non living objects we have two concepts i.e. Monotheism and rest all others like polytheism, paganism, anthropomorphism etc
Following are some references:
The opening verse of the Guru Granth Sahib, known as the Mool Mantra signifies this:
Ik sakgr sat ngm karatg purakh nirabha'u niravair akgl murat ajuni saibha gur prasgd.
" One Universal Creator God. The Name Is Truth. Creative Being Personified. No Fear. No Hatred. Image Of The Undying, Beyond Birth, Self-Existent. By Guru's Grace"
"Chant, and meditate on the One God, who permeates and pervades the many beings of the whole Universe. God created it, and God spreads through it everywhere. Everywhere I look, I see God. The Perfect Lord is perfectly pervading and permeating the water, the land and the sky; there is no place without Him." (SGGS 782)
Guru Arjan, Nanak V, says, "God is beyond colour and form, yet His presence is clearly visible" (SGGS 74), and again, "Nanak's Lord transcends the world as well as the scriptures of the east and the west, and yet he is clearly manifest .
Says Guru Nanak, "budhi pathi na paiai bahu chaturaiai bhai milai mani bhane" which translates to "He is not accessible through intellect, or through mere scholarship or cleverness at argument; He is met, when He pleases, through devotion" (SGGS 436).
Bhagavat Gita 7-[19-21]: All those who do idol worship, All those who worship demigods are materialistic people.
Bhagavad Gita 7:20: Those whose intelligence has been stolen by material desires surrender unto demigods and follow the particular rules and regulations of worship according to their own natures.
Bhagavat Gita 7-22: Endowed with such a faith, he endeavors to worship a particular demigod and obtains his desires. But in actuality these benefits are bestowed by Me alone.
Bhagavat Gita 7-23: Men of small intelligence worship the demigods, and their fruits are limited and temporary. Those who worship the demigods go to the planets of the demigods, but My devotees ultimately reach My supreme planet.
Bhagavat Gita 7-24: The ignorant believe that un-manifest Para Brahma (One God) incarnates or takes manifestations, because they do not completely understand My highest, immutable, incomparable, and transcendental existence.
Yajur Veda 3:32: Of that God you cannot make any images.
Yajur Veda 32:3: na tasya pratima asti
There is no image of Him.
God is formless and bodiless
Yajur Veda 40:8: shudhama poapvidham
He is bodyless and pure.
All those who worship the uncreated things, they are in darkness, and you'll enter more into darkness if you worship the created things.
Yajur Veda 40:9: andhatama pravishanti ye asambhuti mupaste
They enter darkness, those who worship the natural elements (Air, Water, Fire, etc.) They sink deeper in darkness, those who worship sambhuti. (Sambhuti means created things.)
Rig Veda, Vol.6,45:16: There is only One God, worship Him.
Rig Veda, Vol.8,1:1: All Praise are to Him alone
Chandogya Upanishad 6:2:1: ekam evadvitiyam
He is One only without a second.
Svetasvatara Upanishad 4:19: na tasya pratima asti
There is no likeness of Him.
Svetasvatara Upanishad 4:20: na samdrse tisthati rupam asya, na caksusa pasyati kas canainam.
His form is not to be seen; no one sees Him with the eye.
Svetasvatara Upanishad 6:9: na casya kascij janita na cadhipah.
Of Him there are neither parents nor lord.
Thus says the Lord, the King of Israel and his Redeemer, the Lord of hosts: "I am the first and I am the last; besides me there is no god.
To you it was shown, that you might know that the Lord is God; there is no other besides him.
"You are my witnesses," declares the Lord, "and my servant whom I have chosen, that you may know and believe me and understand that I am he. Before me no god was formed, nor shall there be any after me.
"Hear, O Israel: The Lord our God, the Lord is one.
I am the Lord, and there is no other, besides me there is no God; I equip you, though you do not know me,
Jesus answered, "The most important is, 'Hear, O Israel: The Lord our God, the Lord is one.
For you are great and do wondrous things; you alone are God.
That they may know that you alone, whose name is the Lord, are the Most High over all the earth.