Dynamically generate single use Calendly links from your Salesforce email templates.
<messaging:emailTemplate subject="Calendly Meeting Link" recipientType="Lead">
<messaging:plainTextEmailBody>
Schedule an event using the link below:
<c:CalendlySingleUseLink eventTypeUUID="{!$User.Managed_Event_Type_UUID__c}"></c:CalendlySingleUseLink>
</messaging:emailTemplate>
</messaging:plainTextEmailBody>