Textual Inversion, LoRA, and Hypernetworks are advanced features in Stable Diffusion Web UI Online that allow for fine-tuning the weights for the language model and the image de-noiser used by Stable Diffusion. Textual Inversion is a technique for fine-tuning weights for a token in CLIP. LoRA is a method that fine-tunes weights for both CLIP and Unet. Hypernetworks is a method that fine-tunes weights for both CLIP and Unet but shares weights for some layers, allowing for a different approach to fine-tuning.