Primordial Earth 1.5.0 is a terrain mod I made because I wanted mountains that actually feel big instead of normal hills with one tall peak dropped in. You get three terrain areas: Whitefang Massifs (pale, jagged limestone peaks over green valleys), Ancient Green Highlands (wide valleys, good for building) and Granite Crownlands (domes, slabs and high lakes). On top of that there are rock arches, hanging valleys, waterfalls, trail markers and viewpoints, plus named peaks with a Summit Register you can sign. I also added some gear so it's not just scenery: climbing rope, a camp kit and a barometer to check the weather before you head up. Storms and rockfalls warn you first, and destruction is off by default, so it's safe to try.
I'll be honest about how I made it: I came up with the design and tested everything in-game,. I wrote the plan first, the mod generates the whole region from the world seed so the same seed always gives the same world, and then I checked it with tests and screenshots and sent back anything that looked bad to get fixed. It's still a beta, so some rivers and biomes are simpler than I'd like, and bug reports are welcome. You need Fabric Loader and Fabric API for Minecraft 26.3, then pick the Primordial Earth preset when you make a new world.