I was not quite happy with existing solutions for Illustrious based checkpoints with had inconsistent pixel sizes, so I decided to finally try to make a VAE based solution that provides perfect x8 pixel scaling. (This VAE should work for all SDXL checkpoints.) The SDXL latent internally uses a x8 resolution reduction and this VAE tries use this for its advantage for pixel art. It is trained using the pixelation model you probably had to use anyway, but now inbuilt into the model which should hopefully give better results.

My idea was to train a LORA on top of this VAE for the actual style, but for now I found that using pixel art style with Illustrious actually works quite nicely, especially if you do a iteration (or multiple) with img2img.