Sense

1. (with single words and phrases, especially when a negative precedes)
2. (often joined with other particles), (with εἰ ‎(ei)), (followed by a verb)
3. (with a verb omitted)

Examples

• πλὴν κρέασ ἐν αἵματι ψυχῆσ οὐ φάγεσθε. (Septuagint, Liber Genesis 9:4)
• πλὴν ὧν ἔφαγον οἱ νεανίσκοι καὶ τῆσ μερίδοσ τῶν ἀνδρῶν τῶν συμπορευθέντων μετ̓ ἐμοῦ, Ἐσχώλ, Αὐνάν, Μαμβρῆ, οὗτοι λήψονται μερίδα. (Septuagint, Liber Genesis 14:24)
• καὶ ἐπέτρεψε πάντα, ὅσα ἦν αὐτῷ, εἰσ χεῖρασ Ἰωσὴφ καὶ οὐκ ᾔδει τῶν καθ̓ αὑτὸν οὐδὲν πλὴν τοῦ ἄρτου, οὗ ἤσθιεν αὐτόσ.̀ρ̀ν̀ρ̀ν̀ρ̀ν̀ρ̀ν Καὶ ἦν Ἰωσὴφ καλὸσ τῷ εἴδει καὶ ὡραῖοσ τῇ ὄψει σφόδρα. (Septuagint, Liber Genesis 39:6)
• καὶ οὐχ ὑπερέχει ἐν τῇ οἰκίᾳ ταύτῃ οὐδὲν ἐμοῦ, οὐδὲ ὑπεξῄρηται ἀπ̓ ἐμοῦ οὐδὲν πλὴν σοῦ, διὰ τὸ σὲ γυναῖκα αὐτοῦ εἶναι, καὶ πῶσ ποιήσω τὸ ρῆμα τὸ πονηρὸν τοῦτο, καὶ ἁμαρτήσομαι ἐναντίον τοῦ Θεοῦ̣ (Septuagint, Liber Genesis 39:9)
• σὺ ἔσῃ ἐπὶ τῷ οἴκῳ μου, καὶ ἐπὶ τῷ στόματί σου ὑπακούσεται πᾶσ ὁ λαόσ μου. πλὴν τὸν θρόνον ὑπερέξω σου ἐγώ. (Septuagint, Liber Genesis 41:40)

Source: Ancient Greek entries from Wiktionary