What words have the long e sound spelled with i as in unique?

You're right! The "i" in "unique" represents the long "e" sound. Here are some other words with that spelling:

Common Words:

* machine

* police

* fatigue

* marine

* routine

* achieve

* believe

* chief

* field

* fierce

* piece

* siege

* yield

Less Common Words:

* brief

* frieze

* grievous

* mischief

* niece

* priest

* shield

* thieves

* wield

Remember that the long "e" sound can be spelled in various ways, including "ee" (see), "ea" (heat), "ey" (key), and "y" (happy).