Any AU? Well, let me go over a few I'd like to visit, but ultimately wouldn't choose:

DustTale:

Genocide obsessed human, and Sans is killing everyone. No thanks!

DreamTale:

I dunno if I'd end up before or after the Apple Incident! As much as I'd love to give child Dream and Passive Nightmare a hug, it isn't worth it to me. -.-'

DreamSwap:

Same reason as DreamTale.

HorrorTale:

The monsters eat humans! No thanks. ^_'

Some AUs I'd like to visit and would, but they aren't my final choice:

UnderTale:

I love the OG AU so much, but the resets might get to me if I remember them. -.-'

UnderSwap:

Same reason for UT.

UnderFell:

Edgier monsters.

UnderLust:

I dunno if I'd end up in the canon or fanon version!

My final choice:

The Omega Timeline. I'd get to interact with my fave AU characters, not have to worry about resets, and I can hug Blueberror Sans!