Jelly, 6 bytes
*Ɱ4%⁵Q A monadic link which accepts an integer and yield a list of integers.
###How?
How?
*Ɱ4%⁵Q - Link: integer, n 4 - four Ɱ - map across (implicit range of [1..4]) with: * - exponentiate ⁵ - ten % - (powers) mod (ten) Q - de-duplicate