One of the guys I learn from does calisthenics for the vast majority of his training. His name is Jesse Pawlak, nice enough dude but a former convict. He got a felony from back when marijuana was illegal in his state, then got 9 years in the pen for owning a gun with a felony.
Anywho, he's been livestreaming his routine for a year now on youtube, Jesse Pawlak Fast Energy if you want to look him up. It's about an hour in the morning and another hour at night. Morning routine is either a push, pull, or leg movement. Night routine tends to be active recovery, rice bucket, grip hangs, whatever.
He usually just sets a timer for 30 minutes, takes a deck of cards, flips them one at a time (aces and faces equal 10, joker too) and does the reps on the cards. In a deck of cards, that's 400 reps. Takes him like 17 minutes to do 400 reps of bodyweight squats, at a casual pace he can just about do 400 reps of dips in 30 minutes. Even has decent development on his legs in spite of using only bodyweight the vast majority of the time. Then he does some accessories for twenty or thirty minutes and stops.
Other thing about his style (or the style of the prison he was at), is that he only does half of the rep. So majority of the time, that would be like the bottom half rep of the pushup or the top half of the pullup. He claims it keeps all the tension on that particular muscle rather than going through the full range of motion and passing that tension from one group to the next. Hilariously, the science is catching up to this idea lately with lifters like sulek performing half rep dumbbell presses and such.
Standalone, it is obvious that this style of training works. For your average lifter, it is a nice change of pace to do something different for a while if you've been doing the same routine for months/years and you want to do something else.
