http://www.rassegna.unibo.it/autlat.html The original texts of Latin authors (sometimes with concordances, etc.)
http://www.hs-augsburg.de/~harsch/augusta.html#la A collection of literary texts in various languages: for Latin, see “Bibliotheca Latina” (where, under “Auxiliaria”, you will also find a lot of links).
http://latin.packhum.org/ All Latin literary texts written before A. D. 200, as well as some texts selected from later antiquity.
http://thelatinlibrary.com/ The original texts of Latin authors.
http://www.perseus.tufts.edu/hopper/collection?collection=Perseus:collection:Greco-Roman A collection of Latin and Greek texts, containing also some modern commentaries, grammars, dictionaries and essays.
http://www.poesialatina.it/index.htm A website in Italian, about Latin and Greek language and literature; with a section on classical prosody.
http://classics.mit.edu/ A collection of classical (Latin and Greek) texts.
http://ryanfb.github.io/loebolus/ Roman and Greek classics from the Loeb collection (original texts and English translations).
http://www.library.theoi.com/ “A collection of works from ancient Greek and Roman literature in translation. The theme of the library is classical mythology and so the collection presented consists primarily of ancient poetry […], drama and prose renditions of myth.”
http://www.forumromanum.org/literature/index.html “The entire body of Latin literature, spanning from the earliest epigraphic remains to the Neo-Latinists of the eighteenth century.”
http://manybooks.net/language.php?code=la&s=1 53 downloadable Latin ebooks (both ancient and modern works).
http://monumenta.ch/latein/ A collection of Latin texts of all ages.
http://kaali.linguist.jussieu.fr/CGL/index.jsp/ The “Corpus grammaticorum Latinorum” by Keil.
http://bcs.fltr.ucl.ac.be/SLInf4.html A collection of Latin texts translated into French.
http://www.latein.at/elatein-neu/index.php A collection of Latin texts translated into German.
http://www.uni-mannheim.de/mateo/camenahtdocs/camena_e.html “Latin texts of early modern Europe.”
http://www.philological.bham.ac.uk/bibliography/index.htm A bibliography of online neo-Latin texts.
http://www.philological.bham.ac.uk/library.html A “Library of humanistic texts” (mainly poems published in Britain in the XVI and XVII centuries).
http://www.mlat.uzh.ch/MLS/index.php?lang=0 The University of Zurich “Corpus Corporum”: links to various corpora of Latin (and Greek) texts.
http://gallica.bnf.fr/ The site of the French National Library (Paris).