Thanks for the question - I’d never have thought to test this. Fire up a query tool and do the following:
update metabase.report_dashboardcard set row=row+3 where dashboard_id=3
That moves everything in dashboard_id=3 down by 3 rows. Obviously modify to your dashboard ID and how far you want to move them.
You can do something similar with the Size of the charts - you can even make them overlap, but not sure if you can break stuff like this.