I recently purchased some 2D terrain from Playmats.eu, my main purchase was a modular 2D river, but I also bought a couple of 2D hills and 2D broken ground pieces just to try them out.
A lot more pictures and a full review on my blog, but in short I really recommend the rivers. The material, a mix of foam and vinyl is both light weight, soft and easily to customize with a knife if you want smaller pieces. They also look very good imo.
http://anatolisgameroom.blogspot.com/2019/12/2d-rivers-and-terrain-from-playmatseu.html.jpg)
