Nethogs - NetHogs is a small 'net top' tool.

vnStat - vnStat is a console-based network traffic monitor for Linux and BSD that keeps a log of network...

Portmaster - Is a Privacy Modular Privacy App which includes a "DNS over TLS" feature as well as an "Application Firewall".

ntop - ntopng High-Speed Web-based Traffic Analysis and Flow Collection ntopng is the next generation version of the original ntop, a network traffic probe that monitors network usage. ntopng is based on …

LuLu by Objective-See - LuLu is the free open-source macOS firewall that aims to block unauthorized (outgoing) network...

darkstat - darkstat is a packet sniffer which runs as a background process, captures network traffic...