Geoffrey Steadman (free)
Greek and Latin texts with facing vocabulary and commentary. Free digital files for the textbook series written by Geoffrey Steadman.
Gnomon Online (free)
"contains an index to works on Classical Philology, Ancient History, and Archaeology."
Thesaurus Linguae Latinae (TLL) (Open Access Version)
"The Thesaurus linguae Latinae is the most authoritative dictionary of ancient Latin. It is the only lexicon to cover all surviving Latin texts from the earliest times down to AD 600."
Corpus Scriptorum Latinorum (free)
Ancient Latin texts
LATO Library of Ancient Text Online (free)
Ancient Greek texts
The ORB: On-line Reference Book for Medieval Studies (free)
Many books written by medievalists
Perseus Digital Library (free)
"Our flagship collection, under development since 1987, covers the history, literature and culture of the Greco-Roman world"
PHI Classical Latin Texts (free)
"This website contains essentially all Latin literary texts written before A.D. 200, as well as some texts selected from later antiquity."
Thesaurus Linguae Graecae (free)
Collection of Greek literature.
Links to University of London Open Access Classics Resources webpage, providing a multitude of links.