Apart from Ludolf's grammar and Polikarpov's Leksikon mentioned in the highlights, the Slavonic library has two other 17th century items of note. There is a 17th century volume of Canons (Kanonnik 1646) (Arch.A.R257.646) and a Patristic anthology (1665) (o.Arch.A.R257.665) both from the collection of Professor Anne Pennington (1934-81). These are numbered 101 and 128 respectively in the Union Catalogue of Cyrillic books published before 1701.
Cleminson, Ralph [et al.] Cyrillic books printed before 1701 in British and Irish collections: a Union Catalogue London, 2000 (SIMM.Z1013.2000.C9)