Pudding is surprisingly low in calories. Add some chopped banana to chocolate pudding for a tasty snack.
Couscous with chopped tomatoes and cucumber, seasoned with lemon juice and some olive oil, as well as salt and pepper, topped with Feta cheese. Due to the cheese and oil, you couldn't have much of this.
Ganache. I'm kidding, right? But, I happened to have some of this ultra-decadent stuff around that I'd used for a cake. I'd eat like one tablespoon, slowly, and the richness satisfied any sweet cravings. Now, for nutrition or satiety, it's not really great. I once bought some over-the-top chocolatey ice cream. I could only eat a tiny scoop, so it was better for me than the stuff I normally buy where I could eat the whole box!

The same trick can be used with well-seasoned or spicy stuff. So, maybe a blackened chicken breast tenderloin? Or the same tenderloin seasoned like hot wings? Salsa?
Peanut butter on a piece of toast? If you're skimpy with the PB, you could get close to 100 calories. Mine I usually consider 160. It is very filling. If you used celery instead of bread, you could bring it down a lot. There have even been some claims that peanut putter is great for diets.
A long time ago, I used to make some quick "cookie dough". I'd melt some butter with quick oats, then throw in some chocolate chips. It wouldn't bake up, but the oats would be filling and the chocolate chips would help sweet tooth. And, oats are great for you.
One thing to keep in mind is nutrition. You're on a really low calorie diet. You've really got to ensure you're getting proper nutrition in your calories. So, some of my ideas might not be ideal.