Is it possible that an adult could add height (or rather appear taller) by posture correcting exercises? Besides Wall Angel exercise and stretching exercises, what would help? How much could this affect the height?
From what I understand you cannot naturally increase your height as an adult. However you might be able to appear taller with correct posture; doing exercises back and core exercises will help with this.
Some recommendations: Deadlift, Squat, Russian twist, Reverse flyes.
Remember to do those exercises with proper technique otherwise it maybe detrimental in the long run.