Here's a breakdown of how I constructed a Mosaic Tile Floor in Substance Designer. This is a PBR workflow that utilizes the capabilities of the Standard Shader in Unity.
The screenshots of the material are from Marmoset Toolbag.
In researching Roman mosaics for my Rome Fantasy Packs for Unity, it was obvious I needed a way to distribute tiles along a curve. I concluded that I needed to author the textures in a 3d app.
For the swirly patterns and the face: I just made a simple plane, then used the Clone modifier (buy it.. trust me) to specify how many tiles I needed along the proceeding Path Deform (WSM) modifier. I drew a spine that roughly matched the curvature of the swirly helix pattern, bound the set of planes to the spline path, then adjusted the spacing in the Clone modifier so it would fit. Step Build was heavily used to make the tiles for the face. It's the best way!
Bring in the textures to SD, disable vertical tiling, then tile the texture 4-6 times. A tiling band will result, which you can then move into position to the top of the texture. Then copying, rotating, and blending the patterns together so they form a seamless square trim.
The RGBA maps are so I can color it however I wanted in SD by using Color to Mask