It would have to be
Amanda.
Amber is too bodice-ripper and I don't enjoy jewel names anyway; and
Amy was so ubiquitous here about 35 to 15 years ago that if you shouted it, every second head would turn. I exaggerate, but only slightly, and it was never a name I enjoyed, popular or not.
Amanda is good.
Mandy isn't. IRL it wouldn't be worth taking the risk. In a
Noel Coward play, a silly character is trying to ingratiate herself with the central character, a very elegant
Amanda, and says "I shall call you
Mandy!".
Amanda murmurs acidly "Yes, I suppose you will", a sublime put-down wasted on the other woman!