Connecting many electromagnets with polarity control
If you have a lot of magnets (or anything else) arranged in a grid, and you want to power only one at once, in either direction, then what you need is half a bridge on every row and column.
That is, each row or column end needs to be able to be connected to either the positive rail or negative rail. It then forms a full &quot;H&quot; with one side being the end of the row, the other being the top of the column, and the magnet in the middle.

Darlington arrays seem to only come in NPN flavor

You could possibly counteract this by using &quot;high side&quot; switching, where the voltage driving the base of the darlington is higher than the top voltage rail it's powered from. More normally done with MOSFETs.