Physically Based Rendering (PBR) Iray Glass Shader Presets. 

Choose from 15 base presets with different structures for the glass, like glass structures for frosted glass, cracked glass and more (also one clear glass preset is included) and adjust them further with lots of different options, like textures, tints, refraction strength etc. 

For all options there's always a "clear" or "default" preset included to remove the respective adjustment.

You are not limited to the included options since you can freely adjust the appropriate Iray channels to your needs.
Iray is required to use this product. Please note that you only see the actual effect in Iray Preview or the actual render.

Results may vary depending on your setup, like lighting, environment etc.
All image maps are seamless, but it depends on the used object and it's UV if the rendered result is seamless too.