The little scrunchies are nice for night time because they are looser and just enough to keep the hair out of the eyes.
Scrunchie Fun/PonyOs: Top Quality, Handmade Dog Bows - Yorkie, Maltese, Shih Tzu - by BowBiz
The latex free grooming bands are much less harsh on the hair then the regular rubber ones are. They come in a variety of sizes but this size usually works well for a puppy or one with finer hair.
Amazon.com: Latex Free Dog Grooming Bands by... If you don't want to continue to do the topknot thing many Yorkie owners just get the top hair cut so they don't have to deal with the daily topknot routine. I always take out Gracie's topknot at night time. You never want to leave a grooming band in for more than 10 hours (or less if possible) because it does cause damage to the hair.