Idiopathic inflammatory myopathies (IIM), commonly referred to as myositis, are a collection of rare and chronic autoimmune disorders associated with high morbidity and mortality. Especially for one subgroup, anti-synthetase syndrome (ASS), which is characterized by the presence of autoantibodies targeting aminoacyl tRNA synthetases (aaRS). This protein family is most known for its role in protein translation, but recently also new functions and disease connections have been discovered. The pathogenesis behind myositis and ASS is not yet fully understood and there is a high need for better diagnostic tools and more efficient treatments. In this thesis, the aim was therefore to generate high-quality antibodies towards eight targets linked to myositis and ASS, including aaRS, as tools to facilitate further studies. This was achieved with phage display selections using a synthetic human single chain fragment variable (scFv) library. Recovered scFv clones were subjected to a number of validation steps, including ELISA, homogeneous time resolved fluorescence (HTRF), Sanger sequencing and kinetic analysis using surface plasmon resonance. High-performing candidates were identified for all targets and a majority of these had an affinity in the low nanomolar or sub-nanomolar range. Finally, 23 scFv clones have been selected for final validation assays, specificity-ELISA and a cell-based IP-MS, before open access distribution of the sequences to the scientific community, for use in further research. Given an approval in these final validation steps, and along with antibodies that have been generated previously with the same pipeline, a complete set of antibodies targeting all human cytoplasmic aaRS and three aaRS interacting multifunctional proteins (AIMPs) is now available.