From the webpage one can access an overview of the collection with one part in English translation:
Hebrew manuscripts in Complutense University Library
The collection Hebrew Manuscripts of the Madrid Complutensian University Library is formed by 21 codex of Spanish origin, principally from Toledo and contains mainly biblical codices. All the manuscripts were brought together in Alcalá at the beginning of the 16th century by Cardinal Ximenez de Cisneros for the compilation of the Complutensian Polyglot Bible. BH MSS 617 is from Jesuits College of Madrid (Colegio Imperial). Villa-Amil nº 3 was destroyed or missig in the Spanish Civil War (1936-1939)
The majority of the collection is formed by biblical codex (BH MSS 1, BH MSS 2, BH MSS 4, BH MSS 5, BH MSS 6, BH MSS 7, BH MSS 11, BH MSS 12, BH MSS 13 y BH MSS 617). There are, however, three commentaries by Abraham Ibn Hezra (BH MSS 8) and David Quimhi (BH MSS 9 y BH MSS 10)
There is an etymological dictionary with proper names of both the old and new testaments by Alfonso de Zamora (BH MSS 14). By David Quimhi there are five codex: two hebrew dictionaries, Sefer ha-Sorasim, (BH MSS 17 y BH MSS 21) and three hebrew grammars Sefer ha-Miclol, (BH MSS 18, BH MSS 19 y BH MSS 20).
Finally, there are two liturgical manuscripts: Mahzor o sefardic prayer book (Selihot and other liturgical poetry) (BH MSS 15) and a play by Hayyim bar R. Semuel Meir de Tudela, Seror hayyim (BH MSS 16)
Further there is a downloadable inventory and a bibliography.
The bibliography contains several online items. For example:
ORTEGA MONASTERIO, María Teresa (2004). “Spanish biblical hebrew manuscripts”, en Hebrew studies, vol. XLV (2004) pp. 163-174.
ORTEGA MONASTERIO, María Teresa (2006), “Spanish biblical hebrew manuscipts, second part”, en Hebrew studies, vol. XLVII (2006), pp. 67-82.
Read also this post from which one can download a review of Ortega Monasterio's edition of the Masorah of one of the MSS.