Hi there thanks for posting in the Lucid community! I'm afraid we do not have templates that match the exact Structure chart you're looking for but we do have these flowchart diagrams (example 1 example 2) and many other flowchart templates in our Templates gallery here that you might find helpful.

You could also use our flowchart shapes from our Flowchart shapes library to create your own diagram. For more information about this feel free to check out our Create a Flowchart in Lucidchart Help Center article here. If the shape you are looking for is unavailable you can create your own custom shapes following this article as well. 

Feel free to let me know if you have any questions!

Definitely a disappointment. There are a gazillion templates on Lucidhart -- many of them redundant -- it's hard to believe that there's no structure chart templates (with loops data couples control couples etc.).