I tried to post this earlier , but due to the recent forumproblems I'll do it now:
Used and tested by me are a 22" Iiyama, a 13" Beetronics, (or a cheaper chinese version of them) and recently a Waveshare 15,6" portable multi touch screen.
I found the 22" a bit large in theatrevenues where the tech seats are in the audience, specially combined with my Solution, which itself is quite high staying in its flightcase.
After purchasing a FLX I needed a third screen and started looking for something not too small, but modest, and found this 15'6" Waveshare screen. Works very smooth, well-defined touch. And for a portable nice: it has the standard 100x100 Vesa-mount holes. So easy to put on a higher stand.
So two more brands you could probably add to the list: Beetronics and Waveshare. Both brands require no drivers and work with Zeros.