Undertale AUs -- Fiction (fanfiction inspired)

UnderTale AU Roleplay? by ShinySmeargle on DeviantArt

Guardian of the Angel [Undertale Recursive AU]

☆ NIGHTMARE CASTLE ☆ An Undertale AU Dating RPG

UnderDespair

PSA] How to write “Good” Undertale Fanfiction

Undertale AUs, Headcanons, and Other Dumb Things - Flowriel AU

AMA about my lesser known Undertale AU you've probably never heard

Isekai's Undertale - Caitlyn_Henry_Chan - Wattpad

QuatreTale - Undertale AU

fancomic] SAUCY FICTION!! - maximum_overboner, piumpoetam

QuatreTale - Undertale AU

Undertale story ideas - Oh look another fusion Au - Wattpad

13+ Best Stories Sans On Commaful

AU Chronicles] Endertale : r/Undertale

PSA] How to write “Good” Undertale Fanfiction