While single-strain probiotics fail to address community-level microbiota injuries in dysbiosis-related conditions and fecal microbiota transplantation (FMT) produces unpredictable communities, a middle-ground approach has emerged. This approach involves using small consortia of species, combining the precision of single-strain probiotics and the holistic approach intrinsic to FMT. The species selection in this oligomicrobial strategy is typically proprietary or based on studies linking single species to disease or health. To advance this approach, we developed the concept of cohesive modules of engraftment (CME) and a workflow for their identification from FMT trials. CMEs represent small donor microbiota subsets that engraft as units (modularity), while maintaining their original composition (cohesiveness). In benchmarking, we identified >200 highly cohesive CMEs (2-5 species) in 5 FMT trials and found evidence for cross feeding as a mechanism for CME integrity. Due to their predictable post-treatment compositions, CMEs deserve investigation as potential ingredients of future therapeutic microbial consortia.