Try to get oracle 9i. With 9i, there are a couple of sample schemas. One example from HR schema:

SQL> select table_name from user_tables;

TABLE_NAME
------------------------------
COUNTRIES
DEPARTMENTS
EMPLOYEES
JOBS
JOB_HISTORY
LOCATIONS
REGIONS

7 rows selected.

Each table has more than 100 rows. It is good for studying database desgine too.