Health 101: Best Bodyweight Exercises (At Home Workout, No Gym) (Bodyweight Training (BWT))

Basic Bodyweight "Upper Body" Exercises -

1. Push Ups
2. Pull Ups
3. Dips

Basic Bodyweight "Lower Body" Exercises -

1. Squats
2. Lunges

+Optional, Basic Bodyweight "Core" Exercises (For getting 6 Pack Abs) -

1. Plank
2. Mountain Climbers
3. Leg Raises

+Optional, Basic Bodyweight "Full Body" Exercises 

1. Full Burpees 
2. Kettleball Swing

+Optional, Extreme Bodyweight "Full Body" Exercises 

1. Muscle Ups
2. Dragonflies
3. Human Flag
   

Important factors like Time, Reps, Rest & Intensity vary depending on your "personal requirement", which you can be understood through this link.
20 minutes per session, 3 sessions per week.