Greek digraphs

Digraph 2 vowels pronounced as 1 sound.

EI,  ει     reads  as "ee"
OI,  οι    reads as "ee"
YI,  υι    reads as  "ee"
AI,   αι   reads as "e"
OY,  ου  reads as  "ou/u"
AY,  αυ   reads as "av/af"
EY,  ευ   reads as "ev/ef"

Digraph 2 consones  pronounced as 1 sound.

МП, μπ   reads  as "b"
NT,   ντ   reads  as "d"
ГК,  γκ    reads  as "g" (golf)
ГГ,   γγ    reads  as "g" (game)
TΣ,  τσ    reads  as "ts"
TZ,  τζ    reads  as "j" (jazz)