We had the need to test a custom module that came back from assembly in modest quantity. The module is meant to be soldered onto another PCB via castellated pins and is very small.
Holding a multimeter probe (even if it's a PCBite) up to it by hand would be a nightmare so, I designed a little test jig that uses 0.7mm (!) pogo pins (MPN: 1007-D-0.7N-AU-0.49).
The jig is 3d printed with the 0.4mm standard nozzle diameter and surprisingly comes out well. Even if it's hitting the resolution limit of the Prusa.