There are two New South Wales state seats which are due to hold by-elections this year, after the incumbent MPs resigned to run (successfully) in the federal election.
Labor MP Linda Burney resigned from the inner-west Sydney seat of Canterbury to run for Barton, and Nationals MP Andrew Gee resigned from the central west NSW seat of Orange to run for Calare.
I don’t know when these elections will be due, but it will be some time this year.
I’ve completed guides for both seats.