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).
LIM Plugin Collection
A collection of free audio plugins in VST3 and AU formats, developed by the bachelor students of my course "Development of technologies for music production".