RM - Where can I find an agile template to use in Requirements Management?

What version of CLM are you in?
You can use Agile Requirement template while creating a new RM project area.
With 6.0.2 version onwards, CLM also provide SAFe Portfolio template which is based on SAFe4.0 for Scalable Agile teams.

There are three places that you can choose a template in DNG, one of which is a process template, the other two are information structure templates. When you create a project from scratch, you get a small set of information templates from which you can choose, the full set is available from the Templates tab within Project Properties. The only way to get to that tab is to open an existing project. I believe that you need JazzAdmin (or it may be JazzProjectAdmin) to use these. I think that is where you will find the SAFe template.

As I said in my previous answer, there are three places that DNG allows you to choose a template.

1. Project Areas -> Create Project Area: allows you to choose a Process template. The only one supplied is indeed "Requirements Management application template"
2. Lifecycle Project Administration -> Create Lifecycle Project: allows you to choose a structural template for the RM component of the lifecycle project. Just checked, and SAFe Portfolio and Agile Requirements are among the templates provided
3. Inside an existing DNG project -> Manage Project Properties (menu from gear icon at top right). On that page, there are several tabs, go to the one named "Templates" and you will see a list of structural templates. I don't have the necessary *Admin access to see the templates provided.

When you say "the only choice is RM ...", this leads me to believe that you are using the approach in item 1, which, to be fair, is where most people would expect to see templates.