How to make Low Poly Terrain (free) - Unity Answers
OpenGL Low-Poly Terrain Tutorial - YouTube
Assets - WIP Unity Extension for Low Poly Terrain Generation - Unity Forum
Randomly generated low-poly styled terrain with rivers, lakes and erosion - Unity Forum
Working On a Low Poly-Terrain Generator Asset For Unity : r/low_poly
Kristin Lague on Twitter: "Here is a sneak peek of the finished low-poly procedural terrain creator I am currently making in @unity3d. Going to start recording the video next week. #madewithunity #gamedev