Oracle ALL_OBJECTS table

SELECT  *
FROM    ALL_OBJECTS

contains information on objects accessible to the USER (schema)

http://download.oracle.com/docs/cd/B19306_01/server.102/b14237/statviews_2005.htm

SELECT  *
FROM    ALL_OBJECTS
WHERE   OBJECT_TYPE = 'TABLE'

retrieve tables accessible to the user

SELECT  UNIQUE(OBJECT_TYPE)
FROM    ALL_OBJECTS

CONSUMER GROUP
INDEX PARTITION
TABLE SUBPARTITION
SEQUENCE
SCHEDULE
TABLE PARTITION
JAVA DATA
QUEUE
PROCEDURE
OPERATOR
WINDOW
LOB PARTITION
PACKAGE BODY
PACKAGE
LIBRARY
PROGRAM
LOB
INDEX SUBPARTITION
CONTEXT
JAVA RESOURCE
XML SCHEMA
TYPE BODY
TRIGGER
JOB CLASS
DIRECTORY
MATERIALIZED VIEW
TABLE
INDEX
SYNONYM
VIEW
FUNCTION
WINDOW GROUP
JAVA CLASS
INDEXTYPE
JAVA SOURCE
CLUSTER
TYPE
EVALUATION CONTEXT
LOB SUBPARTITION