This type of question has been asked before, but any type of list would be unwieldy and would change frequently, even with just email templates. Still, its a possibility that we might write one up in the future--I'll bring it up with others on the support team.
One way to get at these template variables would be to grep your OCS installation for 'mail->assignParams', which will show all parameters assigned directly to email objects. Other global variables are assigned in the classes/template/TemplateManager.inc.php constructor function--These are variables accessible in any template or email file.
For the track name, try using the variable 'trackName', which is used in certain email templates.
Public Knowledge Project Team