MMP with fractional seats
In MMP, a district seat is typically assigned to the party which nominated the winner of that district. But what if instead we check which parties the winner's supporters voted for and then split the seat among those parties?
For example, if 50% of winner's supporters voted for party A, then that party would get half of the district seat.
As long as every district winner receives more than 50% of the vote this would prevent overhang seats.