This looks interesting
https://youtu.be/k5uKJEF-ZWw I always go here for my RAW terrains:
https://opensimworld.com/hop/82029'
And all these resources: Procedural Terrain Generation: The Worldbuilding School offers a tutorial on generating random terrain using Photoshop's built-in filters. This method involves rendering clouds and applying threshold adjustments to create unique landmasses.
WORLDBUILDING SCHOOL
3D Terrain Mapping from Google Maps: For those interested in creating 3D terrain maps without additional plugins, there's a YouTube tutorial that demonstrates how to use Photoshop to transform Google Maps data into 3D terrain models.
YOUTUBE
Topographic Map Patterns: To create topographic map effects, another YouTube tutorial guides you through designing detailed patterns using a combination of Photoshop filters and techniques.
YOUTUBE
Fantasy Map Creation: If you're aiming to design a fantasy map, Instructables provides a step-by-step guide on crafting a random continent map in Photoshop, covering aspects from coastline creation to biome coloring.
INSTRUCTABLES
Terrain Texture Creation: For those focusing on texturing, CRYENGINE's tutorial explains how to use Photoshop's high pass filter to convert photo source material into seamless albedo terrain textures.
CRYENGINE
That was with a quick AI search. Good Luck on this project :)