We can not vouch for quality, but we do list a number of sources for anti-NPAS4, some of which are supposed to be applicable for IHC. So this may be a good place to start. Just search our antibodies section here:
I recommend to use a free antibody database available at labome.com. For antibodies to NPAS4 you can check the following link: https://www.labome.com/gene/human/NXF-antibody.html. Invitrogen has
rabbit polyclonal anti-NPAS4 ab (catalog: PA5-39300) for IHC. OriGene
provides rabbit polyclonal anti-NPAS4 ab (catalog: TA316290) suitable for IHC. In addition, LifeSpan Biosciences has rabbit polyclonal
anti-NPAS4 ab (catalog: LS-C144924) for IHC. You can read the description of the antibodies and the references following the provided links.