How to extract content from database
There's almost certainly no such thing as "no individual considerations" on Drupal sites.

Even on a Drupal 7 site with no contributed or custom modules, this isn't easy to do.  You might have many content types, with all their fields and associated configuration.

Some tables you'll need to look at are node, node_type, node_revision, field_data_*, field_revision_*, maybe taxonomy_*, maybe others.

Migrate module, Feeds module, and others can help with this too, as Ayesh mentioned.