Here are 20 easy exercises suitable for people weighing 120kg and above:

1. Walking: Start with short, brisk walks and gradually increase the duration.
2. Water Aerobics: Water provides buoyancy and support for larger bodies.
3. Swimming: A low-impact, full-body workout.
4. Chair Squats: Sit in a sturdy chair and stand up, then sit back down.
5. Wall Push-Ups: Stand facing a wall and do push-ups against it.
6. Leg Lifts: Lie on your back and raise your legs a few inches off the ground.
7. Seated Leg Raises: Sit in a chair and extend one leg straight out.
8. Arm Circles: Stand and make large circles with your arms.
9. Standing March: March in place while lifting your knees high.
10. Resistance Band Exercises: Use resistance bands for strength training.
11. Stationary Cycling: A low-impact way to get cardiovascular exercise.
12. Step-Ups: Use a stable step or bench to step up and down.
13. Wall Sits: Lean against a wall in a seated position.
14. Kettlebell Swings: Start with a light kettlebell and use proper form.
15. Planks: Start with short durations and work your way up.
16. Bodyweight Lunges: Step forward and lower your body into a lunge.
17. Yoga: Gentle yoga poses can improve flexibility and strength.
18. Tai Chi: A low-impact martial art that promotes balance and relaxation.
19. Stair Climbing: If possible, use a handrail for support.
20. Chair Yoga: Modified yoga poses that can be done while seated.

Always remember to consult with a healthcare professional or a fitness trainer before starting any exercise program, especially if you have any underlying health conditions. Start slowly and gradually increase the intensity and duration of your workouts as your fitness level improves. Listen to your body, and if an exercise causes pain or discomfort, stop immediately and seek guidance.