Lora of Frisk for Stable Diffusion XL. Was trained on Animagine 3.0 with a dataset that was stacked with non-chibi/superdeformed versions of the character to reduce the chance of distortion.
Prompt is "FriskUT". For game appearance "brown hair,short hair,striped shirt" is recommended. I tried to avoid locking it into any one preferred option. Thus Frisks of varying degrees of masculine/femininity can be made, as can things like using "red eyes" to symbolize the crazed Chara-possessed version.
Fair warning: The shirt still has inconsistencies and can't reliably generate the two purple stripes without inpainting or external editing.