The long I vowel, [aɪ̯], is typically spelled with the letter I as in I, Friday, minor or with the letter Y as in my, cry, July.  It is also spelled:

I:  idea

AI:  aisle

Y:  by

EI:  heist

eigh:  height

EY:  geyser

EYE:  eyebrow

IE:  pie

IGH:  high

UY:  guy

YE:  dye