Give me a source of Hanuman being mentioned in any Purana besides Shiva purana
Devi Bhagavatam:
Lord Hanuman being a form of Lord Shiva, legend as per the Devi Bhagavatam goes like this.
After Sati gives up her life, Lord Shiva ‘s anger knows no bounds. Shiva's rage became so intense that he took the corpse of Sati and wandered around the universe. To reduce Shiva's grief, Shri Vishnu cuts Sati's corpse into different pieces. When Shiva realizes that his beloved wife is cut to pieces by Lord Vishnu, in his anger he curses Lord Vishnu to suffer the same fate.
Later Shiva realizes his mistake and feels regretful. He assures Shri Vishnu that when he would suffer the same fate which Shiva had to go through, he would take a form (Lord Hanuman) to reunite Vishnu (Lord Rama) with his beloved wife Sita, which actually takes place in the Ramayana.
This is how Shiva himself took the form of Hanuman to help Sri Rama in his battle with Ravana to rescue Sita and reunite her with Sri Rama.