There're hundreds!
'A kangaroo short in the top paddock'
'Built like a brick dunny'
'Cobber'
'Good as gold'
'Beyond the Black Stump'
'Back o' Bourke'
'Flat out like a lizard drinking'
'A sandwich short of a picnic'
'Mad as a cut snake'
'Back along the Track'
'Galah'
'Drongo'
'As mad as a two-bob watch'
'Taking coals to Newcastle'
'Don't get ya knickers in a twist'
'That's a Furphy'
'Mine's still running' (slow racehorse!)
Mortein' TV advert 'Louie da Fly'
'When you're on a good thing, stick to it' (old Mortein advert),
AND, of course........
'Tell 'im he's dreamin'................