The Oracle Rdb system tables are as follows:

    RDB$CATALOG_SCHEMA          Contains the name and definition of
                                each SQL catalog and schema. This
                                table is present only in databases
                                with the SQL multischema feature
                                enabled.
    RDB$COLLATIONS              The collating sequences used by this
                                database.
    RDB$CONSTRAINTS             Name and definition of each
                                constraint.
    RDB$CONSTRAINT_RELATIONS    Name of each table that participates
                                in a given constraint.
    RDB$DATABASE                Database-specific information.
    RDB$FIELD_VERSIONS          One row for each version of each
                                column definition in the database.
    RDB$FIELDS                  Characteristics of each domain in the
                                database.
    RDB$GRANTED_PROFILES        Description of roles and profiles
                                granted to users and other roles.
    RDB$INDEX_SEGMENTS          Columns that make up an index.
    RDB$INDICES                 Characteristics of the indexes for
                                each table.
    RDB$INTERRELATIONS          Interdependencies of entities used in
                                the database.
    RDB$MODULES                 Module definition as defined by
                                a user, including the header and
                                declaration section.
    RDB$OBJECT_SYNONYMS         When synonyms are enabled, this
                                system table is created to describe
                                the synonym name, type, and target.
    RDB$PARAMETERS              Interface definition for each
                                routine stored in RDB$ROUTINES. Each
                                parameter to a routine (procedure or
                                function) is described by a row in
                                RDB$PARAMETERS.
    RDB$PRIVILEGES              Protection for the database objects.
    RDB$PROFILES                Description of any profiles, roles or
                                users in the database.
    RDB$QUERY_OUTLINES          Query outline definitions used by
                                the optimizer to retrieve known query
                                outlines prior to optimization.
    RDB$RELATION_CONSTRAINTS    Lists all table-specific constraints.
    RDB$RELATION_CONSTRAINT_    Lists the columns that participate
    FLDS                        in unique, primary, or foreign key
                                declarations for table-specific
                                constraints.
    RDB$RELATION_FIELDS         Columns defined for each table.
    RDB$RELATIONS               Tables and views in the database.
    RDB$ROUTINES                Description of each function and
                                procedure in the database. The
                                routine may be standalone or part
                                of a module.
    RDB$SEQUENCES               Characteristics of any sequences
                                defined for the database.
    RDB$STORAGE_MAPS            Characteristics of each storage map.
    RDB$STORAGE_MAP_AREAS       Characteristics of each partition of
                                a storage map.
    RDB$SYNONYMS                Connects an object's user-specified
                                name to its internal database name.
                                This table is only present in
                                databases with the SQL multischema
                                feature enabled.
    RDB$TRIGGERS                Definition of a trigger.
    RDB$VIEW_RELATIONS          Interdependencies of tables used in
                                views.
    RDB$WORKLOAD                Collects workload information.