From textkit.com, a list of free Greek resources:

Greek Answer Keys

A Brief Introduction to New Testament Greek Key, Samuel G. Green
First Greek Book Key, John Williams White
First Greek Writer Key, Arthur Sidgwick
Greek Prose Composition Key, North and Hillard
Greek Prose Composition Key, Arthur Sidgwick

Greek Composition Textbooks

First Greek Writer, Arthur Sidgwick
Greek Prose Composition, North and Hillard
Introduction to Greek Prose Composition, Arthur Sidgwick
Lectures on Greek Prose Composition, Arthur Sidgwick
Selections from the Septuagint, Conybeare and Stock

Greek Lexicon/Dictionary

First Four Books of Xenophon’s Anabasis, William W. Goodwin
Illustrated Dictionary to Xenophon’s Anabasis, John Williams White
Pocket Lexicon of Greek New Testament, Alexander Souter

Greek Reading Text

Book Twelve of The Odyssey in Greek, Richard A. Minckwitz
Easy Selections From Plato, Arthur Sidgwick
Georgics Book IV in Latin, T.E. Page
Plato’s Apology of Socrates and Crito in Greek, Louis Dyer
Prometheus Bound of Aeschylus in Greek, F. D. Allen
Selections From Herodotus in Greek, W. Walter Merry
The Gospel of St. Luke in Greek, H.R. Heatley
The Iliad by Homer Books XIX – XXIV in Greek, Edward B. Clapp
The Odyssey by Homer Books V – VIII in Greek, B. Perrin
Xenophon’s Anabasis in Greek – Book VI, G.M. Edwards

Greek Reference Grammars

Greek Grammar, William W. Goodwin
Greek Grammar, Herbert Weir Smyth
Syntax of the Moods and Tenses of the Greek Verb, William W. Goodwin

Greek Textbooks

A Brief Introduction to New Testament Greek, Samuel G. Green
A First Greek Course, Sir William Smith
A Short Syntax of New Testament Greek, H.P.V. Nunn
First Greek Book, John Williams White
First Greek Grammar Accidence, W. Gunion Rutherford
First Greek Grammar Syntax, W. Gunion Rutherford
Homeric Greek – A Book For Beginners, Clyde Pharr
Introduction to the Language and Verse of Homer, Thomas D. Seymour
NT Greek in a Nutshell, James Strong

For listing, click here.