Feedback Studio, from Melted Electronics, is a video echo and feedback plugin for After Effects that generates feedback fractals, trails and tunnels. It runs GPU-accelerated for real-time performance and supports After Effects 2020 through 2026.
The plugin includes integrated Luma and Chroma keying, along with feedback translation on the X and Y axes, zoom and rotation. Three mirror modes produce fractal and kaleidoscopic imagery, while Hue, Saturation and Brightness controls adjust the feedback. A negative filter with recursion, plus blur and sharpen, add to the processing options.
Version 1.2.0 added a Remove Source toggle, currently on Windows only. Feedback Studio sits at rank 558 in the aescripts library, and a demo video is available. It's listed as free here, so check the developer's page for current licensing.