When developing a new Drupal 8 site, the following modules are most useful:
composer require drupal/devel; composer require drupal/search_kint; composer require drupal/admin_toolbar;
The easiest way to start developing a Backdrop website is to install the AltaGrade Developer Stack for Backdrop.
However, it requires your local development environment to be setup based on Docksal, which in turn requires Docker. So if are on some other environment and you'd like to start developing a Backdrop site from scratch, then we strongly recommend to install Brush and get the following modules installed:
brush -y en devel brush -y en demo brush -y en search_krumo brush -y en coder_upgrade brush -y en coder_review brush -y en default_views_config