NextGen Bedrock
StarNinjas

Adds an indestructible bedrock layer at the bottom of the world.

Algae
Just_Visiting

Algae mapgen addition to "Minetest Game"

Saltd
runs

Salt Desert Biome

The Road (NC)
Winter94

This is a port of thelowerroad for NodeCore that adds a long road from -Z to +Z to the world, during world-generation.

Skygrid
ROllerozxa

Custom skygrid mapgen.

Experimental Villages Mapgen
Nore

Changes the way ores are placed, add new biomes and villages.

voxelmanip experiments and remade math mandelbox mapgen
chaosomnium

Voxelmanip mapgen with strange layered zone experimental mapgens.

Stonebrick Dungeons
Hamlet

Turns newly generated cobblestone dungeons into stonebrick.

Smaller Steps
Hamlet

Makes stairs and slabs use smaller shapes.

Giant Mushroom/ Mushrooms
Hybrid Dog

Add mushrooms and giant mushrooms.

Technic Plus
mt-mods

Technic fork with focus on features and stability

SkyRealm for NodeCore
Warr1024

SkyBlocks inside vanilla NodeCore

Quartz
Evergreen

Adds quartz ore and some decorative quartz blocks

Natural slopes library
karamel

Library to simply add slopes to regular nodes and include them on map generation and when changing the landscape.

Aquaz
runs

Stuff for oceans

Pyramids (with treasures)
Wuzzy

Pyramids with treasures!

Caverealms
HeroOfTheWinds

A mod for Minetest to add underground realms.

Nether
Hybrid Dog

The underworld for Minetest.

Redwood Biome
runs

Redwood Forest Biome

NC Steam
Winter94

Adds new mechanics to Nodecore, such as steam power and dynamic water

Darkage - the original plus improvements
addi

DarkAge adds several new nodes and crafts to create a pre industrial landscape.

Base Modpack
karlexceed

This combines several other mods that I consider a basic minimum starting point for worlds.

Nodecore Skyblock Ultra Hardcore
Kimapr

The ultimate skyblock challenge

Grave
ElCeejo

Adds an eerie biome with multiple mobs.

Dense Ores
benedict424

Adds rare ores with twice the drops of their normal counterpart.

NC Vulcan
Winter94

Reworks Magma Generation in NodeCore.

Fireflies
Shara

Adds fireflies which can be caught in a net and placed in bottles for lighting.

Fantasy Biomes
Tim7

This adds cool fantasy biomes!

Time Travel
Red_King_Cyclops

Adds in a craftable time machine that can be used to time travel to different time periods of Earth's history.

Magma Conduits
FaceDeer

Removes default mapgen lava and adds widely-spaced vertical lava "veins".

Alien Tools
chaosomnium

Alien Tools Mod for Minetest - adds Alien Tool, Shield, biome, etc

More Coral
Nathan.S

Adds coral in more colors.

Large Slugs
jwmhjwmh

Adds node-based slug mobs to your world

Superflat
srifqi

(Yet Another) Superflat Map Generator: Costumize world generation layer by layer

Australia
demon_boy

Adds a wide variety of Australia-themed biomes and content

New Horizons
Hi_World

Adds 4 new biomes and TONS of new blocks!

PB&J Pup and Nyan Cat
TenPlus1

Adds PB&J Pup, Nyan Cats or MooGnu into your world

Swamps
Hybrid Dog

Adds swamps

Mineclone2 Underwater Challenge
NO11

A survival challenge for Mineclone2. Try to survive in a flooded world.

Subterrane
FaceDeer

A mod that creates vast underground caverns and allows biomes to be defined for them