- Gkrellm - a nice gtk stack of various system monitors
- Dockapps - small applets for WindowMaker (work on most WMs and DEs though)
- lm-sensors - tool to monitor CPU/Motherboard temperature, supports many chips, and differs to ACPI's Thermal Zone
- top - a command line tool to view processes , their pid, cpu usage, memory usage, vm memory usage and cpu time.
- jnettop - a command line tool to view connections on a specific interface (read : eht0, ppp0) that displays remote connection information, port numbers, data transfered per second and other misc features.