I would love to see an Arctic (Snow,Ice) map, A swampland map and a Lava/hades type map. I have the mountain pass(which I love) which does have snow but a more snow ice one would excellent as well. Also a plain flip with green on one side and white(snow) or Green speckled blue(marsh) on the other. Just some Ideas. I've been a DM for a long time and I get a lot of requests for these scenarios.
I use the desert & mountain pass maps all the time.
Great stuff, keep it coming.