Modules are a way for you to package resource configurations for inclusion across stack templates, in a transparent, manageable, and repeatable way. Modules can encapsulate common service configurations and best practices as modular, customizable building blocks for you to include in your stack templates.
Release Notes
AWS CloudFormation StackSets now supports parallel region deployment
You can now choose to deploy StackSets into Regions sequentially or in parallel. For more information, see Stack set operation options.