You can try OAX bounty, they are accepting Newbies but it was running until June: https://bitcointalk.org/index.php?topic=1947373.0

Take a look at the spreadsheets shared around that list bounties. E.g.: https://docs.google.com/spreadsheets/d/1nIkyjAmWz9uW7l6YFaLEMvPf2P7iR8jjSQQXc1x8vYE/edit#gid=0