The good: gas will become temporarily cheaper, which will help consumers of gasoline save money that can either be spent on other goods, or socked away for a rainy day.
The bad: Industries that depend on higher prices of oil (electric vehicles, fracking companies) will suffer.
Could be catastrophic. Banks have lent out half a trillion to fracking companies who need oil to be at least $50 a barrel to be profitable. If those frackers go out of business, combined with COVID-19, combined with literally no ammo left (deficits sky high, rates already super low).... it’ll be 2008 all over again.
This is nonsense. Banks don't fail that easily, your overestimating the relative size of fraking and the idea that the Fed has 'no ammo left' is just nonsense that no the waste majority of monetary economist would disagree with.
Assuming appropriately priced externalities, low oil prices are a boost to global GDP, but harm net oil exporters.