This article explores witchcraft and brujería as ontological designing and as sites of protected knowledge held in common, the generative nature of which threatened operations of colonization in sixteenth- to eighteenth-century Latin America. Witches, both practitioners of the craft but also those whose marginalization and/or resistance to the onslaught of colonialism, capitalism, and Christianity designated them as witches, employed a more-than-human relationality toward transformative ends. Analysis through a design lens foregrounds these magical and healing practices as assemblages wherein agency is co-created with the more-than-human. One manifestation of this is the mundane to magical fluctuation of witchcraft objects, dependent not only on the will and desire of the practitioner but also on intra-actions with other things or phenomena. This plays out in the context of sixteenth-to-eighteenth-century Latin American witch persecutions, where practices were variously gendered, racialized, and tied to ethnic, cultural, and spiritual identities, in a flux of contact and destruction. At times, the persecuted employed brujería as subversive power to negotiate everyday social, political, and economic tensions, particularly as African, African-descended, and Indigenous practitioners who sought to resist hegemonic Western power. They simultaneously protected the knowledge embedded in this relationality while creating a commons of witchcraft practice, accessible within broader communities. This is especially salient for designers who grapple with their relations to the more-than-human and the application of commoning practices to institutionalized and professional design.