Mettaton's written inventory consists of the following:

Lists divided into the following tiers:

LOVE

X	-	+	♥
Caren Cherryblod The King Megumi Mouri Norman Pearl Sigrun Shirazu Speedwagon	Aiden Colress Kamui Lynne Mion Stan Taichi Tarrlok	Black Gabriel Misa Yato Yosuke Mouri Speedwagon Tarrlok Colress Aiden	Aqua Bruce Zagi Cherryblod Sigrun

Drawings
A bunch of really sketchy-quality drawings of people back home. He seems...weirdly fixated on Alphys a lot of the time, there's a lot of drawings of her. Alphys and Napstablook.


Letters
A sketchpad with various letters written to Mettaton's cousin, Napstablook. Most of them don't seem to have gotten very far – they tend to stop immediately after the salutation, the greeting itself scratched out irritatedly, but some of them seem to have gotten a bit farther, despite being cut off eventually anyway:

Dear Bl Napstablook,
Sometimes I wonder if you'll even read this; I wouldn't fault you if you didn't, you know – I never read anything of yours, either. I don't know if I'm sorry for that. If anything, being here has made me realize that I'm not good with that sort of thing. I guess that's ironic


Dear Napstablook,
I'm probably the last person you want to hear from right now, since I'm sure everyone in the Underground is wondering where I've been! I promise I didn't abandon them


Dear Napstablook,
I hope you've found someone else to live vicariously through; I can't be there for you right now but I'm trying to find a way to


Napstablook,
I'm going to die here I'm going to lose but it's going to be fi


Blooky,
I'm so sorry.
- MTT


Blanks
There are several sketchpads that have had a lot of pages ripped out of them; god only knows why. The bright pink envelope from the secrets motive is still around somewhere, but it's empty.