Following some speculation by German tech site 3DCenter, VideoCardz decided to piece together how NVIDIA's next consumer lineup may look like. Keep in mind this isn't really based on leaks, it's mainly educated guessing so take it with a grain of salt. The main premise of VideoCardz's writeup is that NVIDIA may rebrand its existing cards into lower-tier models, similar to what it did with the GeForce 700 series.
This means we may get a GeForce GTX 2080, GeForce GTX 2080 Ti and a new Titan all based on the same GP102 GPU. The GeForce GTX 2060 and GeForce GTX 2070 may share the GP104 GPU, while the GP106 would be rebranded as the GeForce GTX 2050 series.
My theory is that GP104 would be used for two cards GTX 2070 and GTX 2060, with GTX 1080 being rebranded into 2070. This way NVIDIA could introduce GTX 2080 based on cut-down Pascal just before Vega 10. Only then after few months of selling partially disabled chip, NVIDIA could introduce fully enabled silicon with GTX 2080 Ti or TITAN X Pascal 2. Both of these cards are probably going to aim at the ultra-enthusiast market where money is no issue.
Keep in mind this is all just speculation, but the way things look now it's possible there won't be a Volta based lineup until late 2017 or early 2018. Furthermore, it looks like HBM2 isn't going to become mainstream just yet.