Merge of Schnell and Dev variants of the Flux.1 model, almost all blocks are set to different ratios in a smooth ramp from schnell to dev, not a perfect proportion of each model.

Recommended 4-8 steps.

Important

All in one versions include VAE + CLIP + T5XXL (fp8).

UNET versions (Model only) need Text Encoders and VAE, downloads:

GGUF versions require a custom node to work in comfy:

https://github.com/city96/ComfyUI-GGUF

BNB versions (NF4, FP4) require a custom node to work in comfy:

All in one versions: https://github.com/comfyanonymous/ComfyUI_bitsandbytes_NF4
UNET versions: https://github.com/DenkingOfficial/ComfyUI_UNet_bitsandbytes_NF4

Thanks to city96 for gguf quantization script. 
Thanks to reddit user a_beautiful_rhind for bnb quantization script.
Modded 'save checkpoint' node for saving a model without text encoders or vae.
-->  https://github.com/Anibaaal/ComfyUI-UX-Nodes/tree/main

Weights version comparison

Prompts and params at the end.

Samples schnell-fusion-dev (fp8-e4m3fn)

Samples comparing Fusion versions (GGUF are Q4_0, Q5_0, Q8_0)

Test parameters: 8 Steps, CFG 3.5, 1536x1536, seed 0

Prompts:

"Extreme closeup, frog face, star crystal structure, intricate designs, glowing hues. Extreme depth of field, celestial light, shimmering details, otherworldly charm, majestic elegance."
"extremely detailed 3d render portraits of a cyber-dragon themed flaming gothic arcane tech woman, cables, arcane tech-dragon inspired design, exposed machinery. the casing is glittery transparent tinted orange, red and black, allowing to see the internals. sophisticated fantasy design. abstract thematic background. extreme depth of field. dragon behind"
(512x512) "classic pokemon 3DCG illustration. thick outlines. pokemon render style. extremely dynamic composition showcasing the special ability power. flowing pose with extreme closeup on the face in the upper area of the image. intense perspective, in motion movement effects, dynamic impactful vfx, eye catching.. A rock Pokémon with earthquake powers poses dynamically, its body a twisted mass of rugged terrain and molten lava flows. The upper area zooms in on its face, a mask of stone and fury with blazing eyes. Earth shatters beneath its feet as it stomps, unleashing seismic waves that ripple through the abstract background like a fractured canvas. Intense perspective compresses space, conveying unstoppable power. Vibrant colors dance: fiery oranges, electric blues, and smoldering grays. Movement effects blur edges, blurring boundaries between rock and energy. Impactful VFX burst forth in the foreground, echoing the Pokémon's raw force.. masterpiece, professional, best quality, sharp, extreme detail, Hyper-detailed, high-resolution, intricate, vivid. "
"Ethereal female face in 4K ultra closeup, eyes radiating eerie mystical aura with crystalline composition tinted purple-blue hues. Surrounding inferno blazes with dynamic flames and motion effects, creating a vertiginous atmosphere. Extreme depth of field emphasizes surreal otherworldly presence. Glowing eyes at the focal point contribute to haunting mystique, shot from an altered viewing angle emphasizing mysticism. Use Octane and Redshift raytracing for realistic fire and light effects, achieving ultra-realistic 3D render with intense, dreamlike quality."
"Ethereal star princess, diaphanous gown, shimmering stardust, intricate halo, luminous beauty. Night sky, glowing constellations, soft light, dreamy ambiance, mesmerizing allure."
"Sci-fi landscape, derelict alien structure, holographic iridescence, massive metal arches, dark skies, damaged antennas. Ground littered with debris, scattered wreckage, distant moon, dim light."