DBAsupport.com : Oracle 10g Central : Oracle

Select username from dba_users;
SYS
OUTLN
QS_CBADM
PM
ANONYMOUS
SYSTEM
WMSYS
QS_OS
OE
WKSYS
DBSNMP
ORDSYS
QS_ES
RMAN
WKPROXY
SCOTT
ORDPLUGINS
QS_WS
QS_CS
ODM
SH
MDSYS
QS
QS_CB
ODM_MTR
HR
CTXSYS
QS_ADM
XDB
OLAPSYS