People sometimes take out a home equity loan, which is kind of like going in reverse with mortgage payments -- you are going more in debt, using the equity in you built up with previous mortgage payments. If the value of your home increases you have access to a bigger line of credit.

A common use for such a loan is to pay for renovations, which can further increase the value of a property. Another typical use is "home grown leverage" i.e. using a home equity loan to pay for some investment, which is commonly done with rental properties (often to make the down payment on another mortgage; the hope being that you can collect enough in rent to have money left over after making monthly loan payments). For a truly US-only use-case, people sometimes wind up having to use a home equity loan to cover medical bills after a major emergency or accident, though I think this was more common before the Affordable Care Act and will probably become even less common with surprise billing being mostly eliminated.