This is a pool for Haniyasushin Keiki's many misuses of Haniwa.
In the real world, Haniwa are funerary objects, made out of clay in the likeness of people and animals, and are believed to either have been housing for souls or guardians for the dead. As a reflection of this, in Touhou 17: Wily Beast and Weakest Creature, Keiki created an army of Haniwa to protect the humans of the Primate Spirit Garden from outside interference, as their unique nature made them unassailable to the aggressive spirits in the netherworld.
In fanworks, however, they're not quite as... dignified. Starting with the rather... evocative image of Joutouguu Mayumi's haniwa baton, most technology created by Keiki is depicted as a haniwa modified to whatever purpose she needs, from tissue boxes to flat screen tvs. This is a pool to collect the many misuses of Haniwa.
This pool includes:
Haniwa acting as servants do not count, nor do clay animals like in post #4745074 unless they have special functions from being Haniwa. Mayumi's Haniwa baton also doesn't count, unless it is implied to be a sheath or... something else.