I've been creating assets for this lovely piece of software called DUNGEONDRAFT, developed by megasploot, for quite some time now. It's basically a tool that allows me to create a customized mapbuilder featuring my own hand-painted terrains, walls, floors, objects, etc. With over 1000 Art Assets in my base pack alone. All you have to do is download DungeonDraft, and upload my asset packs ,located on the PATRONS page of my website. I've added a showcase video here that can help you figure out how to get started creating a map in my art style, from activating the art assets all the way to putting shadows on your map.
UPDATE 10|02|20 - NATURE 0.1
My latests addition to my DungeonDraft series is a pack called Nature. It currently features about 100 assets with a Forest theme. I plan on updating the nature pack with all sorts of outdoor environments to help you create a range of beautiful outdoor maps on the fly.