Consider most of these done.
ec2 aws ebs s3 cloudfront ami elb
Like you, I'm not sure what to do with the RDS tag, because RDS is as you mentioned a very commonly used Windows tag. Especially now that Terminal Services has actually renamed itself to Remote Desktop services (RDS). I think as there's only 11, then can probably be retagged manually. I have re-tagged the RDS questions. There were only 3 of them. The other 9 relate to terminal services.
On another note, you can create a lot of these synonyms on your own. Just go to the Tag Info page (click on the tag) of the parent tag (so, in this case, all of the amazon tags) and then click "synonyms". Then all we have to do is merge them.
Note to Stack Exchange Employees
As there are > 100 of them, can you please do a delete of amazon from all questions that now contain one of the following:
amazon-ec2 amazon-web-services amazon-ebs amazon-s3 amazon-cloudfront amazon-ami
The remaining amazon questions we will sort out by hand, as there should be a minimal number.
