Requires custom node: https://github.com/city96/ComfyUI-GGUF
fluxFusionDSSmoothMerge4StepsAIO_v0GGUFQ40.zip
fluxFusionV24StepsGGUFNF4_v1GGUFQ40.zip
fluxFusionDSSmoothMerge4StepsAvailableInGGUF_v0GGUFQ40UNET.zip