I LOVE Washi paper tape (Japanese masking tape). It instantly adds a bit of charm to a letter or a package and it's great for different crafts, journals, scrap books ... everything!
When we were in Japan, I stocked up! Well, I stocked up as much as I possibly could without someone telling me that I couldn't possibly need 12 rolls of tape. Ha! It's kind of difficult to find in stores here, but you can purchase it online from happy tape or from many different shops on Etsy. These are all from PrettyTape.