α β γ δ ε ζ θ κ λ μ ν ξ ο π σ τ υ φ χ ψ ἀ ἁ ἄ ἅ ἆ ἐ ἑ ἔ ἕ ἠ ἡ ἤ ἥ ἦ ἧ ἰ ἱ ἴ ἵ ἶ ὀ ὁ ὄ ὅ ὑ ὕ ὗ ὠ ὡ ὤ ὥ ὦ ὧ ᾄ ᾅ ᾠ ῥ

Letter ἠ has 3 occurences.

Count word def
4 ἠλί my God
165 Ἠσαῦ Esau, an Edomite
5 ἠχέω to make a loud noise, i.e. reverberate