2.
Your own trash can that CLOSES.
4.
A standup hamper that is also a bag.
5.
A multipurpose bottle opener.
8.
An extra set of sheets.
9.
An electric tea kettle.
10.
A bed bug mattress protector.
14.
A cushion for your uncomfortable desk chair.
17.
Adhesive hooks and nails.
19.
A good, durable backpack.
20.
Some form of alternate lighting.
and probably the single most important item on this list:
23.
AS MUCH UNDERWEAR AS PHYSICALLY POSSIBLE.