A clever zero-cost alternative I've seen some manufacturers use is a 1xN PTH footprint with every other hole offset slightly (~20 mil) to the side. The misalignment is just enough to make a straight pin header get stuck in the holes.

There's an example of this on Digilent's Arty development board, at the top of the board between JB and JC:

https://digilent.com/shop/arty-a7-100t-artix-7-fpga-developm...

That's very cool. Thanks. At first I thought they were just press-fit pins (see https://www.te.com/content/dam/te-com/documents/automotive/g...) but they are not!

More here: https://www.we-online.com/components/media/o210254v410%20ANE...

Very nice alternative to Tag-connects. It looks like the PCB footprint is a little larger per pin but the connector is less fragile and the connection would be more robust. Great for having a debugger or logger attached during lifecycle testing especially in the prence of vibration. I also find their other suggested use - enabling expansion connections with no added cost to the base unit - very intriguing. "Options" are very typically higher margin than base products so having a way to enable adding them that does not add a connector to every unit has a lot of potential use cases.

This is exactly what I was looking for!

(In case anyone missed it, there is a video on the page that explains how it works)