battery monitor

CPU, RAM, network, disk, and weather monitor.

Access remote sites and monitor live video.

German Fritz!Box call monitor and call manager.

Setup & monitor Xserve RAID volumes.

Add a second menubar to a dual-monitor setup

A financial monitoring app that allows users to monitor stocks.

Signal/status monitor for Huawei E220 HSDPA USB modem.

Real-time visual stock market index monitor.

Plugin for Mail.app takes advantage of widescreen monitor.

It can monitor newsgroups on several different servers, and download many files.