Data Dictionary Views That Contain User and Profile Information

View	Description
ALL_OBJECTS	Describes all objects accessible to the current user
ALL_USERS	Lists users visible to the current user, but does not describe them
DBA_PROFILES	Displays all profiles and their limits
DBA_TS_QUOTAS	Describes tablespace quotas for users
DBA_OBJECTS	Describes all objects in the database
DBA_USERS	Describes all users of the database
DBA_USERS_WITH_DEFPWD	Lists all user accounts that have default passwords
PROXY_USERS	Describes users who can assume the identity of other users
RESOURCE_COST	Lists the cost for each resource in terms of CPUs for each session, reads for each session, connection times, and SGA
USER_PASSWORD_LIMITS	Describes the password profile parameters that are assigned to the user
USER_RESOURCE_LIMITS	Displays the resource limits for the current user
USER_TS_QUOTAS	Describes tablespace quotas for users
USER_OBJECTS	Describes all objects owned by the current user
USER_USERS	Describes only the current user
V$SESSION	Lists session information for each current session, includes user name
V$SESSTAT	Lists user session statistics
V$STATNAME	Displays decoded statistic names for the statistics shown in the V$SESSTAT view

Oracle data dictionary views

Oracle dynamic performance views