These eleven tables do not belong in a group of tables.
There are four primary node-related tables. There are many relationships to the node table and another to the node_type table that reach into other table categories.
There are four taxonomy tables:
There are four tables for search:
There are four tables related to Drupal blocks:
Eleven of the 74 core Drupal 7 tables are to support caching. Below, each of these tables are enumerated and their purpose is described:
Drupal is a registered trademark of Dries Buytaert.