Net-SNMP - Net-SNMP
SNMPSoft Tools - A set of SNMP tools to get, set, walk SNMP tree.
qtmib - SNMP MIB Browser
SnarlSNMP - Download snarl-snmp for free.
OpenSNMP - Download openSNMP for free. openSNMP is a multi-threaded SNMPv3 engine. This project supports the Simple Network Management Protocol version 3.
JMibBrowser - Download JMibBrowser for free. JMIBBrowser is a java based MIB Browser. It supports GET and SET queries for SNMP enabled devices.