Underverse is an animated comic created by JakeiNimation on Tumblr. A basic explanation is that, Underverse is a large crossover that highlights a variety of popular alternate universes that fans of Undertale have created. The comic is currently a work in progress, but regardless, I believe it deserves a decent dub along with more attention. A link to the original comic is pasted below. Happy auditioning, and good luck!
Due to the fact that the creator of this comic is still working on it, if you are casted, be prepared to be called back throughout a long period of time in order to dub new episodes.
Also, as the comic continues, it's expected that new characters may be introduced, so watch for updates.
https://underversesans.tumblr.com/post/142978216345/underversesans-00-part-one-the-first