I used Substance Designer for the surfaces, world projected landscape layers to remove seams at the edges of tiles as they are placed procedurally by the designers mission generator and I later added distance blend masks to remove repetition. Same as the building material I also added dynamic snow\puddles.
SpeedTree was used for the foliage\grass then I built a Shader that supported dynamic snow, colour changes for the seasons and a sprite for the distance.
Materials done in -Ue4 Landscape/Ice/Lava/Foliage/Rocks
Speedtree assets - Material/Integration/LOD's/Optimization
Landforms/Rock's/Ice Chunks - Material/Integration/LOD's/Optimization
World height Based Snow
Puddles based from height map