Trailbender
Trailbender is a versatile delay-based multi effect plugin that can be tweaked to act as a mod fx, a pitch shifter, a synthesizer, and other things.
Test-Signal Generator
Test Signal Generator is a VST and AU plugin that lets you generate many kinds of test signals in order to help you inspect hardware and software systems (such as outboards or plugins).
ScatterWords
ScatterWords is a simple Windows application that lets you scatter each line of a text file over a 2D blackboard in order to manually cluster text data.