There are some non-profits specializing in buying up medical debt and forgiving it (e.g. RIP Medical Debt [0]). These non-profits usually rely on individual donations, and $100 can relieve as much as $10,000 of medical debt. They also frequently rely on donations from other organizations such as churches [1]. There are examples of churches buying up tens of millions of dollars worth of debt [2]. I'm not aware of this being done for other kinds of debts, although I would assume it happens.