Any Modules organized/tagged in the Warehouse in the Templates category are made available as templates when new modules are created from the Start New button:

To appear on this list, the Module must be in the Templates category.

Modules can be organized in the Warehouse under any categories added in Admin - Warehouse Options. Only Templates will be made available when starting a new Module.

Modules can be moved into and out of this category at any time.

This can be handy for moving Modules in and out of "active status", to keep the list of available Templates manageable, and focused on the most important learning scenarios.