WEEKLY GAME JAM
Weekly Game Jam is a great chance to polish your programming skills while having fun. It lasts one week and has some great themes. They don't have limitations other than needing to create the game from scratch. Link below.
MINI JAM OFFICIAL
Mini Jam Official is a short 72 hour Game Jam on itch.io that adds limitations to the theme. Sometimes it can be as challenging as only three inputs allowed. Link below.