In weightlifting, drop sets have you starting with a certain weight and performing as many reps of the exercise as you can, and then dropping the weight a bit to continue the lift and so on. With body-weight calisthenics, we decrease the resistance by changing something in the mechanics of the movement, such as the foot position or the angle of the body in relation to the ground. Here is an example for a pull micro-workout, starting with pull-ups. Once I get near my limit, I move the feet to the ground and keep going. When that gets almost impossible, I change my angle slowly towards vertical (or standing straight up) and keep going. I like to keep the total reps for these sets in the 20s.