You could try stuff like squats, Calf Raises, Lunges+most abdominal exercises require little to no equipment. But thats just off the top of my head, i haven't done a bodyweight routine in a very long time.
Maybe if you fill up a water bottle or something equivalent you could just treat that as a little dumbbell and do lateral raises, bicep curls, tricep kick backs, shoulder press etc
May have to do some higher receptions on the exercises though but once you have some form of weight to use, you can get very creative.