Best python github Repositories very helpful for beginners -

1. scikit-learn : https://github.com/scikit-learn 

2. Flask : https://github.com/pallets/flask 

3. Keras : https://github.com/keras-team/keras 

4. Sentry : https://github.com/getsentry/sentry 

5. Django : https://github.com/django/django 

6. Ansible : https://github.com/ansible/ansible 

7. Tornado : https://github.com/tornadoweb/tornado 

*Beware click the link!