Potassium and fibre, among other vital nutrients that we completely overlook when focussing on calories and macros.
If you want something filling that has barely anything to it, hit up pumpkin/butternut squash and salads more. Decided to actually measure everything I put in my salad the other night, and for something that filled me up quite well (given my appetite and stomach capacity, this is decent), it came to 66 calories LOL