I have purchased and host www.free3dgamemaker.com. It is a repository for quick links and information to some of the best open source software for game making. I will be using all of the information to develop Ambardia from now on. I invite you to explore the site as well.
Castle Gates: DAZ 3D models imported into Unity.
Forest Models: Modeled in Blender.
Browse the site, read the descriptions, take the courses. It's all free for the taking.
Have fun and make that dream game!