The first phase in unconventionals formed around productive US shale gas plays. High margin US tight oil plays defined the second wave. Small US producers are now leading the third phase, applying horizontal drilling to a range of underexplored, technically-challenging strata. These plays may not need to be as aggressively developed, nor be as large in scale, as plays in the first phases. This template, taking hold in the Lower 48, will be an integral model to exploit international assets.