V$PROCESS | 
Contains information about the currently active processes | 
V$SESSION | 
Lists session information for each current session | 
V$SESS_IO | 
Contains I/O statistics for each user session | 
V$SESSION_LONGOPS | 
Displays the status of various operations that run for longer than 6 seconds (in absolute time). These operations currently include many backup and recovery functions, statistics gathering, and query execution. More operations are added for every Oracle Database release. | 
V$SESSION_WAIT | 
Displays the current or last wait for each session | 
V$SESSION_WAIT_HISTORY | 
Lists the last ten wait events for each active session | 
V$WAIT_CHAINS | 
Displays information about blocked sessions | 
V$SYSSTAT | 
Contains session statistics | 
V$RESOURCE_LIMIT | 
Provides information about current and maximum global resource utilization for some system resources | 
V$SQLAREA | 
Contains statistics about shared SQL areas. Contains one row for each SQL string. Provides statistics about SQL statements that are in memory, parsed, and ready for execution |