I’ve made a script to create an Orabbix/DBforBIX user with the minimum grants available.
CREATE USER ZABBIX IDENTIFIED BY <REPLACE WITH PASSWORD> DEFAULT TABLESPACE USERS TEMPORARY TABLESPACE TEMP PROFILE DEFAULT ACCOUNT UNLOCK; GRANT ALTER SESSION TO ZABBIX; GRANT CREATE SESSION TO ZABBIX; GRANT CONNECT TO ZABBIX; ALTER USER ZABBIX DEFAULT ROLE ALL; GRANT SELECT ON V_$INSTANCE TO ZABBIX; GRANT SELECT ON DBA_USERS TO ZABBIX; GRANT SELECT ON V_$LOG_HISTORY TO ZABBIX; GRANT SELECT ON V_$PARAMETER TO ZABBIX; GRANT SELECT ON SYS.DBA_AUDIT_SESSION TO ZABBIX; GRANT SELECT ON V_$LOCK TO ZABBIX; GRANT SELECT ON DBA_REGISTRY TO ZABBIX; GRANT SELECT ON V_$LIBRARYCACHE TO ZABBIX; GRANT SELECT ON V_$SYSSTAT TO ZABBIX; GRANT SELECT ON V_$PARAMETER TO ZABBIX; GRANT SELECT ON V_$LATCH TO ZABBIX; GRANT SELECT ON V_$PGASTAT TO ZABBIX; GRANT SELECT ON V_$SGASTAT TO ZABBIX; GRANT SELECT ON V_$LIBRARYCACHE TO ZABBIX; GRANT SELECT ON V_$PROCESS TO ZABBIX; GRANT SELECT ON DBA_DATA_FILES TO ZABBIX; GRANT SELECT ON DBA_TEMP_FILES TO ZABBIX; GRANT SELECT ON DBA_FREE_SPACE TO ZABBIX; GRANT SELECT ON V_$SYSTEM_EVENT TO ZABBIX;
NOTE: If you have made some custom query you need to grant the select privilege on your used tables.