@Rascal thank you for posting about this loo paper. I’ve just ordered some. What a great business-Australian made 
gives 50% of their profits go to the RSPCA and they are double length rolls of recycled soft material
They also have tissues in the same cute packaging.
Each home owner is unique so, like most things house-sitting related, there isn’t a one-size-fits-all solution. I have bought or brought things to use in the house while I’ve been house sitting and left small items, like a dish brush. However, I think a home owner might assume you’d left behind a pot or pan if you left it there. It might be worth taking it with you in case another sit doesn’t have these items.
For essential items, I bring my own food, cutting board, sharp knife, and cleaning supplies.
While I am repeatedly puzzled by the lack of many essentials and abundance of many non-essentials in various homes, if you can bring along things that are important to you and then accept with what people have available in their homes, this is the gig for you. After all, it’s free housing!
As someone else mentioned also, I am a HO I specifically say “NO GIFTS” in my instructions. Gifts are just clutter to me. I say follow the directions and do a nice job taking care of the pets and home and that’s gift enough.
We usually leave a very clean home, a bouquet of flowers and a welcome home card from the pets! We also wash and dry the bedding and towels if time allows- to save the HO a job on arrival. Most hosts are really appreciative of all this.