Late last year I created a console application for moving access team templates between Dynamics CRM organizations, and I described it in this blog post. Following up on that, I've created an XrmToolBox plugin to make it even easier to move access team templates (with GUIDs) between CRM organizations. I've also added functionality to automatically enable access teams on the relevant entities in the target organization if desired.
Let's take a look at the tool in action.
Before execution
Here are the access team templates in the source organization. 
Here are the access team templates in the target organization before we run the tool. 
Note the "Dog" entity does not have access teams enabled. 
Running the tool
First open XrmToolBox. Look at that handsome dog! 
Next select the Access Team Template Mover plugin and connect to an organization. That organization is set as the source, but you can change it. 
Click the select target button to select the target organization. 
Once both source and target are set, the copy templates button will turn green and become enabled. 
You can also uncheck the option to automatically enable access teams for target organization entities. If you do, you will receive a confirmation prompt. 
Executing the copy with the enable access teams for target organization entities option checked copies three records in this scenario. It updates the access team template that already existed in the target and creates two new ones. 
After execution
Because the enable access teams for target organization entities option was selected, the "Dog" entity in the target now has access teams enabled. 
Finally here is the updated list of access team templates in the target organization. 
Getting the plugin
The source code for the plugin is available in my GitHub repository here.
The compiled plugin can be downloaded here.