We can't update item to SNMP agent using Mass update option. It is always shows error - "Invalid parameter "/1/snmp_oid": cannot be empty."
But "snmp_oid" option is not available. So, we have SNMP agent in type list, but can't change it.

Steps to reproduce:
1) Create item with type - Zabbix agent.
2) Navigate to items list.
3) check in created item and press Mass update button.
4) Change Type parameter to SNMP agent.
5) Press Update.

Result:

Expected:
1) SNMP OID parameter exists.
or
2) SNMP agent removed from type list.

UPD: Same goes for
1) "Database monitor" item type.
We can't mass update to Database monitor, error appears like:
"Invalid parameter "/1/params": cannot be empty.". And also this parameter doesn't exists in mass update form.
2) SSH agent.
Error message - "Invalid parameter "/1/params": cannot be empty.".
3) TELNET.
Error message - "Invalid parameter "/1/params": cannot be empty.".
4) Calculated.
Error message - "Invalid parameter "/1/params": cannot be empty.".
5) IPMI agent.
Error message - "Invalid parameter "/1/ipmi_sensor": cannot be empty.".

We have all this items Types in mass update list, but technically we can't change them because of missed parameters.