Consider most of these done.

[tag:ec2] [tag:aws] [tag:ebs] [tag:s3] [tag:cloudfront] [tag:ami] [tag: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.

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 [tag:amazon-] tags) and then click "synonyms". Then all we have to do is merge them.