Abd al-Rahman bin Yazid and Abd al-Rahman bin al-Aswad (may Allah have mercy on them both) mention that Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) used to prostrate at the first verse (of prostration) in the surah "Ha Mim. A revelation from the Most Gracious, the Most Merciful."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8705