Mathematical challages that can be completed in Python (Updated Regularly)
https://projecteuler.net/
Karan Projects
https://github.com/karan/Projects
Programming Exercises
https://github.com/zhiwehu/Python-programming-exercises/blob/master/100%2B%20Python%20challenging%20programming%20exercises.txt
Python Challenge
http://www.pythonchallenge.com/
edabit
https://edabit.com/challenges
checkio
https://py.checkio.org/
Code wars
https://www.codewars.com/landing?language=python
r/dailyprogrammer
https://www.reddit.com/r/dailyprogrammer/
Codingbat
https://codingbat.com/python