To build layouts
a) using Foundation
https://www.drupal.org/project/zurb_foundation
https://www.drupal.org/project/foundation_layouts
https://www.drupal.org/project/layout_plugin
b) using Omega
https://www.drupal.org/project/omega
To manage blocks any of them
a) https://www.drupal.org/project/ds
b) https://www.drupal.org/project/page_manager
c) https://www.drupal.org/project/panelizer
d) https://www.drupal.org/project/context
e) https://www.drupal.org/project/block_visibility_groups
To add "fields" (paragraphs) dynamically to content
a) https://www.drupal.org/project/paragraphs
To control fields visibility
a) https://www.drupal.org/project/form_mode_control