my_list = [{'hi' : 11, 'there' : 28}, {'how' : 11, 'are' : 31}, {'you' : 28, 'Will':31}]
print("The list is:")
print(my_list)

my_result = list(set(value for dic in my_list for value in dic.values()))

print("The result is :")
print(my_result)

The list is:
[{'there': 28, 'hi': 11}, {'how': 11, 'are': 31}, {'Will': 31, 'you': 28}]
The result is :
[11, 28, 31]