The bed of the Messenger of Allah ﷺ was made of leather stuffed with palm fibers.
حدثنا أبو توبة حدثنا سليمان يعني ابن حيان عن هشام عن أبيه
كانت ضجعة رسول الله ﷺ من أدم حشوها ليف
No references are available.
Reference. [Sahih] Ibn Majah narrated it in the Book of Zuhd, chapter "The bedding of the family of Muhammad" ﷺ, no. 4151, from the hadith of Sulayman bin Hayan Ahmar, and Muslim, no. 2082. See also the preceding hadith, from the hadith of Hisham with the same wording.