This is work done over time by me while exploring terrains in Unity I use other external tools too. However usually my target is to eventually import them to Unity and see how they do. I'm always looking to make realistic terrain landscapes - I love it really much and found it really entertaining and challenging while at it!
Please do keep in mind that almost none of my terrain experiments in here has additional vegetation or geometry imported - they are almost all plain and bare terrains with only a skydome and water bodies added. I should be doing a series of experimentation with more complete and up to date environments soon. Is definitely on my near future plans! XD I'll just love to be able to do so.