You can make sugar-free jello with whipped cream. (this is the standard dessert)
you can have anything as long as you stay under the 20g carbs. Beef jerky is good too but it has carbs unless you make your own. You can drink the diet drinks but some people get stalled if they take in a lot of aspartame. Some people don't get affected.
Keep everything in moderation and you'll be fine.