These two Female Stacking Headers alone are, well, lonely. But pair them with any of Adafruit's Feather boards and you're in business!
What do they do? They stack. Put the headers through your Feather and then you can not only plug them into a solderless breadboard, but you could attach circuitry on top as well
Note: Comes with one 12-pin and one 16-pin header, Feathers not included