Triplanar material functions often overlook normal maps because they require correction in order to appear accurate.
This plugin includes clearly labelled, well-structured material functions which can be reused anywhere in your project for good-looking, accurate triplanar texturing.
Also includes demo materials with annotated material graph which explains how the functions are optimised for performance. These optimisations allow you to use the function for multiple textures, for example in a PBR workflow, with minimal extra overhead.
Read documentation: Advanced Triplanar Material Documentation
FreePBR.com
The demo materials use PBR textures from FreePBR.com which has over 500 high quality texture packs available to download. They are all fully compatible with this material function and I highly recommend them.