Here are some PNG texture that
can be used for bitmap fills in CC3
A few of these textures are user textures posted at
www.dundjinni.com
To use these, I do an import bitmap fill style in CC3 then use the fill style property to use the png file as a bitmap.
You may have to mess with the scale on some of these PNG fills to get the desired scale you need to the size of the overland map you are making.
Dirt 1 Grass1 Grass 2 Grass 3 Grass 4 Grass Rough Mossy Stone Sand