AWS SMS metrics not showing in CloudWatch data source

I can see all of the built-in AWS namespaces in the drop-down for my CloudWatch data source, and I can plot EC2, SES data etc. just fine. But when I go to AWS/SNS I do not see any of the SMS metrics listed.

I’m expecting to see some of the special SMS stats in there, which are a subset of SNS. For example in the AWS Console, I can select, Country, SMSType which allows me to plot the SMSSuccessRate

Any ideas why this might not be showing up?

That metric list is hardcoded in - please create pull request and add there that SMS metrics.
Anyway you can try to write SMS metric name into input box manually.