Here is a pretty old thread discussing the sealed Ancient Mew variants: Sealed Mew Insert Variants.
But to show some example pictures:
Australian:
Danish:
Norwegian:
Swedish:
UK:
US:
These are all just pictures I’ve saved. I don’t own any of these above, not even the regular US sealed version. (Although I do have all six Ancient Mew as PSA-10 graded copies. 
)
I do have the almost complete set for the Moltres promo however. I’m only missing the Danish variant, although I’m still not sure whether that insert exists for the legendary birds or just the Ancient Mew, since I have yet to see any proof for any of the three birds.
Greetz,
Quuador