xcol is an inventory of the endless invention that is integral to any ethnographic inquiry. It takes as its departing point the idea that ethnography is an act of invention: Anthropologists, and ethnographers in general, have to invent how to investigate with others. xcol documents and curates the relational inventions produced by anthropologists with their counterparts. The inventory offers four kinds of inventions: fieldwork inventions for ethnographic inquiry (field devices), pedagogical methodologies and venues for the apprenticeship of ethnography (open formats), interventions towards the inside of the discipline of anthropology drawing inspiration from our fields of study (intraventions), and material experiments in anthropological practice at the hinges of the ethnographic (prototypes). Anthropologists, ethnographers and close companions are invited to join this open inventory.