Awesome, I love it, and so quick! Thank you so much!
Love the littler trees, the giant stumps, and ohh there's soo many snowman now - I especially like the deer one! Thanks as well for the tents and gates, and all those mushrooms and flowers, its going to make my level so much more varied! The stairs are fantastic!
Wall Colors - For the walls, since it is winter, I was thinking it would be great to have a wall that's made of snow (similar to the style you've got on the left of Tileset 3, with the white-lightblue-blue) and one that is made of frozen ice (similar to the style at the top-right of Tileset 3, with the diagonal stripes).
Wall Sizes - I think it's important to be able to make taller walls, so it would be fantastic to have wall-top, wall-middle and wall-bottom that can be combined. It's also really important that these include diagonal pieces as well.
PS: If you make additions like these, it might be better if you could put them onto new sheet/file, as changing the dimensions of the current files may make it difficult for people to re-import into their game engine without affecting their current tile palettes and level tilemaps. A great way to avoid this problem is to make each tileset a fixed size, fill it up from top-left to bottom-right, and when its full, simply make a new one.