Fastcycles is an add-on for Blender's Cycles render engine built around a single-click interface. Instead of manually configuring Cycles settings, you switch between three optimized presets: Draft for a very fast rough with good quality, Medium for high quality at low render time, and High for high-end settings aimed at a high-end result.
The presets cover a range of render needs, from quick previews to final output, and are selected directly rather than adjusted one setting at a time. Render examples on the developer's page show timing differences across the three presets, illustrating how each option trades speed against quality.
Distributed under the MIT license and compatible as a Blender extension, Fastcycles targets Blender 4.3. It is a Dev Fund contributor listing, and a demo video is available. For anyone working repeatedly in Cycles, the add-on packages preset switching into a small, focused interface.