The Messenger of Allah ﷺ used to pray on a small prayer mat.
أخبرنا إسمعيل بن مسعود قال حدثنا خالد عن شعبة عن سليمان يعني الشيباني عن عبد الله بن شداد
أن رسول الله ﷺ كان يصلي على الخمرة
No references are available.
Bukhari narrated it in the Book of Prayer, chapter on praying on the khumrah, hadith 381, from the hadith of Shubah, and so on, hadith 513, after that hadith 660, from the hadith of... and Muslim in the Book of Mosques, chapter on the permissibility of congregation in optional prayer, from Sulayman Shaybani, through him. It is also found in Kubra, hadith 817.