The ALD provides searchable access to the complete corpus of medieval translations of the works of Aristotle. Included is an extensive help guide in PDF that explains the structure of the database, available searching options, transliteration methods, etc.
Past Masters provides access to the complete editions of philosophy texts originally published in the print series. Also included are several dictionaries including the Oxford Classical Dictionary.
From website: "The Philosource federation contains an extensive, multilingual collection of reliable scholarly editions of philosophical texts, high quality reproductions of primary sources and a rich archive of videos including lectures and interviews featuring leading contemporary philosophers."
The Selected Digital Primary Sources for History guide contains an extensive list of resources which may be useful for your research. The guide is organized by geographical region.