When you say liquid, there are 2 types, a clear liquid diet and full liquid. Not sure which you will be on but typically ppl are on clear first then full liquid.
For clear liquid I had:
Chicken/Beef Broth
G2 or Vitamin Water (for the electrolytes)
Jello
Herbal Tea (Chamomile did wonders for my stomach)
Once I progressed to full liquid (the liquid should roll off spoon like milk)
100 calorie greek yogurt that has been thinned with skim milk and strained to remove fruit seeds/bits
Cream soups (potato, cheese, broccoli) that are made with skim milk, and then thinned with skim milk and strained
I made peanut butter bananna smoothies using skim milk, greek yogurt, banana, and PB2 (powdered peanut butter) IT WAS DELISH (just strain first)
Also Trop 50 OJ cut with 50% water has been a great way for me to get a big old scoop of protein powder down in the morning.
I've also had Coco wheats made with skim milk, thinned with skim milk and a little sweetener.
Don't go out and buy a ton b/c you are going to be shocked at how little you can actually consume!!
I'll be moving to puree/soft foods in about a week so I'll let you know what stuff seems to work well for that stage