I've been asked to recreate this holographic foil effect on a 2d plane:

https://media.giphy.com/media/dqLLqZVJtSb0Jwac64/giphy.gif

Specifically the specks picking up different reflections as the card turns.

I think I've got quite close using the Metallic Flakes setting in a Redshift Car Paint shader:

https://media.giphy.com/media/H0ZlEwWe5YDRQKGZeS/giphy.gif

But I really want to be able to define my own noise / pattern.

In this example the reflections are following a pattern that changes with the angle of reflection:

https://media.giphy.com/media/6SygzX0SItLkkwTJvh/giphy.gif

Does anyone have an idea how I would achieve this?