The most used grout company in the USA is Custom Building Products. There are two main types of cementitious grout, Polyblend Plus and Prism.
Polyblend is a traditional polymer modified cement grout, and Prism is a high performance, lightweight, fast setting cement grout.
For the grout testing video I mentioned:
https://youtu.be/g3TtkEkgefs
To purchase waterproofing membrane, tools, and tile supplies go to https://www.tilecoach.com/shop
To order 1:1 consultations, go to https://www.tilecoach.com/book-online
For more info on Tile Redi products, select the links below:
Redi Trench: https://tileredi.co/3ZXQp0p
Redi Base: https://tileredi.co/45AznGK
Custom Shower Pans: https://tileredi.co/3tHpGJu
Wall Solutions: https://tileredi.co/3tD8K6G