This site, administered by Gerd van Riel at the Katholieke Universiteit Leuven, is an evolving bibliography, last updated in 2012.  Two separate pages are devoted to the major late Neoplatonists, Proclus and Damascius.  They are both relatively complete, including works on general topics addressing the author(s).  One cannot search the page, but the entries can easily be browsed.  There is also a list of editions and translations of their works, many of which have appeared only recently.  Along with the Hellenistic Bibliography, then, this site offers a promising starting-point for online bibliographiesofr non-Patristic Greek authors in Late Antiquity.

http://hiw.kuleuven.be/dwmc/ancientphilosophy