Royal Darwin Show - late July
Ekka (Brisbane) - August
Royal Adelaide Show - early September
Royal Perth Show - mid September
Royal Melbourne Show - late September
Royal Hobart Show - October
I reckon Royal Darwin Show is the most likely to be held next year provided there are no cases in NT by then.
UPDATE 28/8: This year’s Royal Hobart Show, scheduled for October, has already been cancelled, however the Show Day public holiday will still go ahead.