1. Large Ziplock Bag (gallon or larger) - Great for separating dirty clothes, or any number of random uses.
2. Detergent - I typically don't pack a lot of clothing so the likelihood of running out of clothes is high, and I'm very picky with my detergent (Seventh Generation Lavender is my favorite).
3. Tea Tree Oil - Amazing for muscular pain. I used to carry a full 1 oz bottle, but this vial takes up less space.
4. Nail Clipper - I had to buy one on a trip, so now that I have two I keep one in my suitcase so I don't forget to pack it.
5. Sanitizing Hand Wipes - Sometimes traveling gets grimy (especially in third world countries), and not everywhere has soap (especially in third world countries...)
6. Mint and Echinacea Herbal Teas - Good for indigestion and for fighting a cold before it starts (respectively).
7. Cedar Block - Keeps my clothes smelling fresh.
8. Sewing Kit
9. Extra Cell Phone Battery - An older one that lasts half as long as my current one, but could come in handy nevertheless.
10. Extra Glasses
11. Bikini - Barely takes up space, and you never know when you'll stumble upon a pool, hot tub, mineral pool, or sauna.
12. Large Bubble Wrap Envelope - If I purchase something breakable, it's nice to have the extra protection for it.