I think we ought to make a distinction between
(a) those instructional works that we ordinarily call "textbooks" or even "primers" but perhaps including "intermediate" or "second-year" textbooks. We ought also to distinguish Biblical Koine textbooks from Classical Attic or Homeric textbooks.
Among the Biblical textbooks I would include Funk and Goetchius, Machen, Mounce, Croy, etc.
Among the Classicall Attic textbooks I would include Athenaze, JACT Reading Greek, Chase & Phillips, Crosby & Sheaffer, Mastronarde, Hansen & Quinn, etc.
Among the Homeric textbooks, I would include Clyde Pharr and Benner's Selections from the Iliad.
(b) reference grammars that are to be consulted in the process of exploring particular questions, especially morphological and syntactical, arising in reading or research
Here I would include especially H.W. Smyth's Greek Grammar, Blass-Debrunner-Funk (BDF),A.T. Robertson, Wallace (GGBB), Brooks & Winbery, etc.
οὔτοι ἀπ’ ἀρχῆς πάντα θεοὶ θνητοῖς ὑπέδειξαν,
ἀλλὰ χρόνῳ ζητέοντες ἐφευρίσκουσιν ἄμεινον. (Xenophanes, Fragment 16)
Carl W. Conrad
Department of Classics, Washington University (Retired)