SNMPSniffer is an open source (GPLv3) desktop application with a graphic interface to sniff SNMP packets in the network. The process can be optionally filtered by ip, ports, direction (source or destination). The data can be optionally saved into a file.
Github repository: calaverastech/snmpsniffer
The application requires packet capturing software installed, such as libpcap (libpcap-dev or such for Linux).