Another interesting proposal I've heard, and quite like is: corporations are not allowed to buy homes. Ever.

They can own them if they build them (which is necessary for organisations that build social housing, for example), but if they sell, they have to sell to people. A bank may come to own a house when the original owner can't pay the mortgage anymore, but if the bank wants to sell the house, they have to sell it to a person. Other than that, any corporation that wants to own houses, has to build them themselves thereby expanding the housing supply, instead of shrinking it by buying existing houses.