from collections import Counter

l = [1,3,4,7,3,2,6,9,5,0,3,6,1,6,3,8,6,7,2,5]

c = Counter(l)

c

Counter({1: 2, 3: 4, 4: 1, 7: 2, 2: 2, 6: 4, 9: 1, 5: 2, 0: 1, 8: 1})

c.most_common()

[(3, 4),
 (6, 4),
 (1, 2),
 (7, 2),
 (2, 2),
 (5, 2),
 (4, 1),
 (9, 1),
 (0, 1),
 (8, 1)]

c.most_common(3)

[(3, 4), (6, 4), (1, 2)]