In Shri Shiv Mahapuran (published from Gita Press Gorakhpur), there is knowledge about father of Brahma, Vishnu and Shiv.
Evidence: - Shri Shiv Mahapuran, in Rudrasamhita Khand, from page 100 to 110, there is the following account: -
While giving answer to his son Narad ji’s question, Shri Brahma ji said that - O Son! The question that you have asked about the creator of the universe, listen to its answer.
In the beginning, there was only one “Sadbrahm” remaining. There was destruction at all places. That formless God made his appearance like Shiv. He is called “Sadashiv”. He took a woman out of his body. That woman came to be known as Durga, Jagdambika, Prakriti Devi and Mother of Tridev (Brahma, Vishnu and Shiv). She has eight arms and is also called Shiva.
Note: - Here, consider Shiv as Kaal Brahm, Shiva as Durga. Dear Readers! In this Rudra Samhita Khand, there is no account of the birth of Shankar ji. This is a mistake of the translator. However, in Devi Puran (Shrimad Devi Bhagwat Puran), Shankar ji has himself admitted that I have taken birth from Durga (Prakriti). In Shiv Puran also there is evidence that Shankar Ji is the son of Shiv and Shiva (of Kaal and Durga).
Evidence: Shri Shiv Mahapuran, Vidhveshwar Samhita Khand, Page 24 to 30: -
Once, Shri Brahma ji and Shri Vishnu ji started fighting on this subject that Brahma ji said that I am your father because this world has originated from me; I am the father of the people. Vishnu ji said that I am your father; you have originated from my navel-lotus. They both became ready to hit each other. At that very moment, Sadashiv, that is, Kaal Brahm placed a white radiant pillar in between those two. Then he himself, appearing in the form of Shankar, told them that none of you is the creator. Excerpt from Shiv Puran given below.
Oh sons! I have given you two tasks of production and maintenance of the world. Likewise, I have given two tasks of destruction and death to Shankar and Rudra. I have been called Brahm in the Vedas. I have five mouths. From one mouth, Akaar (Aa), from the second mouth, Ukaar (u), from the third mouth, Mukaar (ma), from the fourth mouth, Bindu (.), and from the fifth mouth, sound (shabd) have appeared. Uniting these five components, one word ‘Om’ has formed. This is my original mantra.
The following has been proved from Shiv Puran
This same evidence is also in Shrimad Bhagavad Gita Chapter 14 Verse 3 to 5 that Raj (Rajgun Brahma), Sat (Satgun Vishnu), Tam (Tamgun Shankar), the three gunas have originated from Prakriti, that is, Goddess Durga. Prakriti is the mother who gives birth to all the living beings. I (the Speaker of the knowledge of Gita) am the father of all the living beings. I place the seed in the womb of Durga (Prakriti) by which everyone is produced.
Bhagavad Gita Chapter 14 Verse 3
O Arjun! My Primeval Prakriti i.e. Durga is the womb of all the living beings and I, Brahm-Kaal, place the seed in that womb. By that union all the living beings are born.
Bhagavad Gita Chapter 14 Verse 4
O Arjun! Whatever embodied beings are born in all the wombs, the Primeval Prakriti (Durga) is their mother who conceives them and I, Brahm-Kaal, am the seed-giving father.
Bhagavad Gita Chapter 14 Verse 5
O Arjun! Satvagun (Vishnu), Rajogun (Brahma) and Tamogun (Shankar), these three gunas born of Prakriti bind the eternal soul to body.
Shrimad Devi Bhagavata Puran - Third Skand, Adhyay 5, page no. 123
Shri Vishnu Ji praising Durga Ji says - ‘you are a pure figure. This whole world is arising from you only. I (Vishnu), Brahma and Shankar, we all exist by your grace. We take birth (aavirbhaav) and die (tirobhaav). Only you are eternal. You are the universal mother /Jagatjan-ni / Goddess Prakriti (existing for time immemorial).
God Shankar said - ‘Goddess, if the greatly fortunate Vishnu has taken birth from you, then Brahma who was born after him, must also be your son only, and then am I, Shankar, who does Tamoguni Leela, not your child ie. you only are my mother too. Your Gunas are always present everywhere in this world’s creation, preservation, and destruction. Born of these three Gunas (qualities), we, Brahma, Vishnu, and Shankar, remain devoted to work according to the regulations’.