The Gazi Husrev-Beg Library in Sarajevo, Bosnia, houses various Islamic manuscripts including Qur’ānic mushafs, Hadīth manuscripts, works on Tafsīr, and more.
The oldest manuscript is a copy of Imam al-Ghazali’s Ihya `Ulūm al-Dīn copied during the lifetime of the author himself.
Below is a link to a small publication By Dr. Mustafa Jahić containing some information about the library along with images of some of the manuscripts housed within:
at-Tahawi 
Would love a post on the manuscripts used by certain editors which deliver quality and authenticity in their new researched books published such as in Hanafi fiqh and otherwise.
Al-salam ‘alaykum,
I am assuming that you are speaking about editions and editors for Arabic books. Is that correct?