I have always (i.e. for about fifty years) been an advocate of learning the roots of all verbs, but most especially of the irregular verbs that undergo unpredictable alterations as they combine with other verb-formative elements. My active teaching was concentrated in Classical Attic and I have compiled my own list of Attic Greek irregular verbs, accessible at http://www.artsci.wustl.edu/~cwconrad/d ... 0Roots.pdf
I've also prepared a list of GNT Irregular verbs that I've drawn up from the vocabulary of Mounce's Basics of Biblical Greek, indicating frequency in the GNT, basic English meanings, principal parts, form(s) of the simple root of the verb, and some comment on idiosyncracies of each verb.http://www.artsci.wustl.edu/~cwconrad/d ... rbsGNT.pdf
These can be downloaded directly from those URLs, or from a page of "Course Materials from Years Past" that I've kept online from my years of active teaching:http://www.artsci.wustl.edu/~cwconrad/current.html
Carl W. Conrad
Department of Classics, Washington University (Retired)
ἄτοπον, ἔφη, λέγεις εἰκόνα καὶ δεσμώτας ἀτόπους.
ὁμοίους ἡμῖν, ἦν δʼ ἐγώ. Plato, Rep. 7 (515a)