wmnet polls network statistics and does a few things with the data it gets. It has small blinking lights for the rx and tx of ip packets, a digital speedometer of your tcp/ip stack's current speed and neatest of all, a bar graph like xload et. al which has a tx speed graph from bottom-up and rx speed graph from the top-down. The speedometer keeps track of the current speed per second and shows it in a color corresponding to which of rx or tx that has the highest speed at the moment.
WMpop is a Window Maker dock app that monitors a local (mbox format) or POP3/APOP mailbox to inform you when mail arrives. It displays the amount of mail in the mailbox (or unread mail if checked in the preference screen), a scrolling text with the email address of the senders (only for local mailbox at the moment) and a status led, indicating mail checking progression and errors. It can be configured and personalized (icons and sound) via a GTK+ GUI.
WMScript is a system monitoring dock app for Window Maker. It allows you to specify a command and have the numeric result of that command displayed in the dock app's window. You may specify up to 5 things to monitor and the interval is configurable. This combines to make it a very flexible tool for system monitoring. It is based on WMiNet, and the look is the same.