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.
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.