Hello!
I know this post is from 2016 but I can think of one green screen pattern for walls and floors that came with the Spa Day pack. It's not perfect but from what I saw it's the purest green option. The only possible downside is that it's a little bit animated. There is a slight change in brightness over time, but I have still been able to use it in photoshoots (never tried with videos though).
Anyway if anyone is still interested in that, it is called "The Glow That Flows" and it can be found in the misc category of the wall and floor patterns.
