Substrata is a Vanilla+ based mod that adds on features that follow in Vanilla's footsteps.

Newest Update:
V-1.2 - Adds a whole new list of Amber Blocks and Ores to the game

Feature List:

Limestone, Limestone Bricks, Polished Limestone Block Sets
Marble, Marble Bricks, Polished Marble Block Sets
Shale, Shale Bricks, Polished Shale Block Sets
Slate, Slate Bricks, Polished Slate Block Sets
Granite Bricks, Diorite Bricks Block Sets
Amber Block Sets
Framed Amber Block Sets
Chiseled Amber Block Sets

Prehnite Armor, Tool Set, and Ore

(Prehnite is found in Limestone, weaker than diamond, more durable than it)

Biomes:

Lush Waters (Contains Shale underwater, similar to lush caves but smaller)
Limestone Caves (Huge caverns filled with limestone on the ground)
Crystal Caverns (Has marble, and boosted chances of emeralds and gold)

I plan to add much more to this mod, so I started small for the beginning, so I can actually feel like working on it, and if you are a creator or are working on a modpack, feel free to use this; no credit needed.

If you find anything wrong or bugged within the mod, please let me know. You can leave a message here or directly DM me.