Hi
You can download HPE Systems Insight Manager - MIB Kit from below link.
https://support.hpe.com/hpesc/public/docDisplay?docId=emr_na-c04272529
This kit provides all the necessary MIB files to update HPE SIM, or any other MIB tool, to have the latest support for HPE ProLiant and Integrity servers.
Please refer Compiling and customizing SNMP MIBs with HPE SIM document (Page number 15 to 18) to get information about MIB's.
http://h20628.www2.hp.com/km-ext/kmcsdirect/emr_na-a00002871en_us-5.pdf
To Monitor hard drives, power supply etc.. you can use below two MIB's.
cpqstsys.mib HP Proliant Storage
cpqhlth.mib HP Proliant System and Environmental