Wolf Plugins has recently released an open source waveshaper distortion effect plugin for Windows, Mac and Linux.
Wolf Shaper allows users to create custom waveshaping functions using 4 different curve types in a spline-based graph editor.
Warping algorithms are available to alter the graph dynamically. Uni/Bi modes let you switch between symmetrical and asymmetrical distortion, and the plugin comes with up to 16x oversampling to remove aliasing artifacts for a cleaner sound.
Wolf Shaper is available to download in VST/VST3, LV2 and CLAP plugin formats.
More information: Wolf Plugins