Atop - An advanced interactive monitor for Linux-systems to view the load on system-level and...
iftop - iftop does for network usage what top(1) does for CPU usage.
htop - htop - an interactive process viewer for Unix. This is htop, an interactive process viewer for Unix systems. It is a text-mode application (for console or X terminals) and requires ncurses. Latest release: htop 2.
vnStat - vnStat is a console-based network traffic monitor for Linux and BSD that keeps a log of network...
Stacer - Ubuntu system optimizer
nload - Monitor network traffic and bandwidth usage in real time