Ok! So, I was able to get some more answers from the Sans! So here they are:
( ShyGuyRedstone ) Legacy: The sound of train station bells.

Wow, that's actually a really unique one! I wonder what that would sound like...

( MadEmmagirl ) Error: A metronome, you know, to keep a music tempo. It's... soothing I guess.

I actually don't know what a metronome is. :P

( Underswap12 ) Reaper: The screams of people who are being gripped by death, and pulled into the most forgotten places IN THE WORLD!

Reaper! You're so evil! Take a chill pill!

( Underswap12 ) Reaper: Yeah, like that'll help... *snicker*

You aren't you when you're hungry. Have a snickers bar. Lol :3

( chichimang ) Fem Dream: Hmm... cars. It's nice to hear them go by.

( Master_Unknown ) Blueberry: Dang it... Um... I guess the sound of a pretty music box.

Ooh! Remember the Easter egg where you can get the music to play out of the statue?

Wait... Idea!
(Play music above!)

I believe that's all of the answers I got back. If apparently not all the Sans replied than I'll update, yet again. I'm fine with it though. See you in the next chapter! Bye!