For consumers, there are three new PCB boards; the PG180, PG160, and PG150, all three have a model number that starts with 699. A photo of the PG180 board leaked a couple of days ago, presumably that is the GeForce GTX 2080 (or 1180). For the professional side, the website also lists PG150, PG160, and PG180 boards that start with "900". Those are likely Quadro and Tesla parts.
The two other boards: PG150 and PG160 are most likely for different GPUs. At launch, we usually only see one, sometimes two boards going through the certification process. So what this means is it that NVIDIA has at least three new GPUs ready.
The third and fourth parts of the product codes define variants of the boards (power circuits, display connectors, cooling mounting and even the color of the PCB).