WapSNMP is an SNMP client library for Go. It allows you to query SNMP servers for any variable, given its OID (no MIB resolution). It has been written to be in the Go style, which means it should be very resistant to all error conditions. It's entirely non-blocking/asynchronous, very fast, and will timeout, not block. It's also surprisingly small and easy to understand. It supports SNMPv2c or lower (not 3, due to its complexity), and supports all methods provided as part of that standard. This library works with OIDs and does not support OID-to-name translation.
LibreNMS is an autodiscovering PHP/MySQL-based network monitoring system forked from Observium. It aims to be easy to use and painless to deploy, and to support monitoring of a wide range of devices. Observium's license changed to a modified QPL license in May 2012, then was split into free and commercial versions. The aim of LibreNMS is to continue to create a usable NMS, but with a community focus and GPL licensing.
snmp4zabbix provides a simple SNMP interface to the Zabbix monitoring solution. This lets Zabbix monitor itself using the Simple Network Management Protocol. This is an alternate solution to the Zabbix API for integration, to some extent, with any third party software capable of understanding SNMP.
snmp2xml is a program to convert snmpget output to XML. The output from snmpget, snmpwalk, or snmpbulkwalk is first filtered to correct for SNMP agent flaws and then processed into XML. This XML can be passed through xmllint to tidy it up or it can be processed by an XQuery or XSLT processor. The XML output represents all the SNMP data such that the original SNMP output can be reproduced if desired with an XSLT stylesheet (which is included). The snmp2xml converter has been tested on 7 SNMP agents: Mac OS X, Apple Time Capsule, the Billion ADSL router, the Huawei S9306 switch, the Foundry/Brocade CES and MLX-4 switches, and the Nortel 425 switch.