WMgMon is a generic monitor applet for WindowMaker and Afterstep. It can display CPU, I/O, memory, and swap usage, as WMMon does. It can also display the result of other programs, as WMScript does. The result can be displayed as a gauge, a histogram, a percentage, a number, or any combination of those. WMgMon's advantage is that it lets you configure what's displayed in its configuration file so that you can tailor it to your preferences and easily extend it by adding new monitoring functions and new scripts.
tcsysmon is a dock app that monitors Mem/Swap/DiskIO/Uptime and displays blinky lights for your interrupts and page in/outs. Its goal is to display as many real-time system statistics as possible with a minimum of CPU usage. It includes MMX routines for faster updates on newer CPUs.