"Canada and Australia have signed a mutual agreement that allows young Canadians between the ages of 18 and 35 to travel and work in Australia for up to 12 months. (The age limit used to be 30, but it was increased to 35 in 2018)."

Canadians appear to be a special exception though. If you're Australian, most countries still limit you to age 30 (and Cyprus & South Korea limit you to 25 or younger, apparently):

https://global-goose.com/working-holiday-visas-for-australia...