Having just discovered this community, I compiled all my book icons out of my old icon posts. 32 icons. Some Harry Potter, some Good Omens and many many Hornblower (spoilers for Retribution).
Most of these icons are from Nicholas Upton's De studio militari (MS. Holkham misc.31 at the Bodleian, dating from the second half of the 15th century). The final five are from another Bodleian manuscript of the same period (MS. Lat. misc. e. 86).