We are making strides in OCRing Migne's Patrologia Graeca: Here is a text processed last year; here is a similar one processed in 2014.
We have many collections of fragments, papyri, etc, such as Kock, T. Comicorum Atticorum Fragmenta 3 and Koerte's fragments of Metrodorus of Lampsacus.
Complete or near-complete series include the volumes in Commentaria in Aristotelem Graeca, Cramer's Catena Graecorum Patrum, and Meyer's Critical and Exegetical Handbook series of biblical commentaries.
Teachers of ancient Greek might be interested in Rouse, W. H. D. A Greek Boy at Home, A Story Written in Greek. or these Greek grammars.
Lexica and glossaries have great potential for data-mining.
Unusal fonts processed include this Bekker edition of Aristotle, published by Reimer.
The Loeb editions provide facing translations, useful for natural language processing. OCR provides access to volumes from this series that have not yet been digitized, such as Cary's Roman Antiquities of Dionysius of Halicarnassus, Eusebius, Galen, On the Natural Faculties and Julian.