Amazing can be abbreviated? If so, what letter does it stand for?

No one has abbreviated this word. I don't think you are the first. Since it is the first one, let's shrink boldly. It doesn't matter. Since you said it's not for writing articles, it's ok to use it in public. You made a big fuss about this abbreviation the other day. Maybe the abbreviation Amazing will be replaced by what you think in the future. It doesn't matter much if you are wrong anyway. You can write amz or amzg with the initials Amazing. That's it. It's not for you to explain. Words without abbreviations have abbreviations themselves, which were invented by others. You just think it makes sense. Besides, there is no standard to measure whether your abbreviation is right or wrong.