I suggest using a free antibody database at labome.com. For antibodies to STAT6 you can check the following link: https://www.labome.com/review/gene/human/STAT6-antibody.html. Abcam has STAT6 antibody (Abcam, ab28829) was used in immunohistochemistry - paraffin section on human samples (Southworth et al, Respir Res. 2016). GeneTex has STAT6 antibody (GeneTex, GTX113273) suitabel for IHC.
Cell Signaling Technology offers STAT6 antibody (Cell Signaling, C11A12) suitable for WB. Santa Cruz Biotechnology provides STAT6 antibody (Santa Cruz Biotechnology, sc-1689) suitable for both IHC and WB. You can read the description of the antibodies and the references following the provided links.