Therapeutic antibodies have become important drugs in the field of targeted therapy because of their high specificity to target antigens. Currently, over 100 antibody drugs have been approved for the treatment of various human diseases, yet the targets covered are indeed limited, with approximately half of these drugs targeting only 10 common targets. Approved drugs encompass not only monoclonal antibodies but also antibody-drug conjugates, bispecific antibodies, and antibody fragments. The scarcity of antibody drug targets and subsequent conjugation or engineering modifications pose challenges for the development of novel antibody drugs. In response to the growing demand for fully human antibody drugs, Biocytogen’s antibody discovery team has generated a library of antibodies targeting hundreds of antigens using fully human antibody transgenic mice (RenMice). Our RenMice undergo additional gene-editing procedures to knock out designated target genes. Subsequently, antibodies obtained by conventional immunization have a wide range of epitope-binding properties to homologous protein targets, but also exhibit cross-species reactivity. We have completed over 900 fully human antibody target projects and established a library containing over four hundred thousand off-the-shelf fully human antibody sequences. The antibodies generated from RenMice can be used in a variety of applications, and many of the TAA (tumor-associated antigen)-targeting antibodies have been screened for internalization activity to ensure suitability for ADC development. In addition to fully human monoclonal antibody derived from RenMab platform (fully human immunoglobulin variable domains replacing the mouse loci), RenLite-derived common light chain antibodies are easy to assemble into bispecific antibodies (BsAb) with low mismatch rate and ideal physiochemical properties, which are suitable for BsADC, biparatopic antibody (BpAb) and other modalities. Small and flexible fully human nanobodies based on RenNano platform (fully human heavy chain only) also provide solutions for specific antigen epitopes or multi-targets, multi-epitope antigens. Thus, the fully human antibody library can accelerate the development of antibody drugs.