This is a hard question to answer, as it tends to be industry based.
But some extra perks I'll list below.
Fully maintained company car inc parking, sometimes a driver is included depending on your rank in the company.Not so common since after the 1997 hand over though.
If you have children, a debenture and full schooling costs, either here, or paid boarding schools internationally, including all travel costs to and from during school holidays.
Debenture and membership at Hong kongs more exclusive country/yacht clubs supplied.
Mortgage contribution of about 80K per month, was a common ( Aviation )Check/Training Captain perk based on 5 year contracts, contributed for not longer than 15 years.
2 trips home each year for you and your family ie wife and kids if applicable, flying business class.
Company supplied mobile comminications, ie Blackberry.
A pre determined bonus payment at the completion of a contract period, not usually less than 80K, ie school teachers at the Aus International school got that one.
I am sure there's a few more, but these are some of the extra perks I am aware of.

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