never taken talc anywhere!
Small amount of hand sanitiser for when washrooms are a 'challenge'.
Depending upon the type of places you'll be sleeping in, a door wedge is a very small but effective way of preventing people from entering your room while you sleep.
If you like a bath, a squash ball is an effective, multi-sized bath-plug.
FIRST AID KIT! (and know how to use it!)
Smoke detector is probably more likely to be of use than a carbon monoxide detector, again depending upon the environment you will be staying in.
Photocopy of passport and other essential documents in case of loss/theft. Included upon them, important contact details.
A tip that I thought was excellent but never got around to doing...A pen & a roll of gaffertape. Wind some tape repeatedly around the pencil. You've now got an emergency repair kit for suitcases etc but in a manner that takes up minimal space and a pen is always handy anyway.
With the internet more & more widely available, on line storage for backing up photos etc. If you lose your camera/memory card you've still got your precious images. Also, most people don't realise that about 80% of the time, images can be recovered from a corrupt or accidently formatted memory card, as long as it hasn't been re-used.
You going some place then?