Downloads
Python 3: https://www.python.org/downloads/
Pycharm: https://www.jetbrains.com/pycharm/download/ (community edition)
Tutorials
PY4E videos: https://www.py4e.com/lessons coursera course: https://www.coursera.org/specializations/python
Programiz: https://www.programiz.com/python-programming/
LearnPython (especially good if you know another language): https://www.learnpython.org/
W3schools: https://www.w3schools.com/python/
Video Tutorials
Python in 4 hours: https://www.youtube.com/watch?v=rfscVS0vtbw
Python Course: https://www.youtube.com/watch?v=_uQrJ0TkZlc
Practice Problems
Edabit: https://edabit.com/challenges
Hackerrank Python Collection: https://www.hackerrank.com/domains/python
Website: http://usaco.org/
Codeforces (contest website similar to USACO, with more regular contests): https://codeforces.com/
Guide (very helpful): https://usaco.guide/
Past USACO Contests for practice (very helpful): http://usaco.org/index.php?page=contests
USACO Tracker Spreadsheets to use with above: https://codeforces.com/blog/entry/78158
Discord Server: https://discord.com/invite/bessMBe
Forum: https://forum.usaco.guide/
Reddit: https://www.reddit.com/r/usaco/
AoPS Forum: https://artofproblemsolving.com/community/c163h1992134_usaco_forum
What is USACO?: https://artofproblemsolving.com/community/c1147805h2116498
Website: https://www.acsl.org/
Content Review (very helpful): https://www.acsl.org/get-started/study-materials (Junior division)
Leaderboard: https://www.scores.acsl.org/
Tangerine Code: https://www.youtube.com/channel/UCIClxIg2yUTex4ZPJG0osAA/videos
Quick Coding Bytes: https://www.youtube.com/channel/UCOGjZxSfKQ-4w3NBOHT5Mdg/videos