Mineclone2 New Ores and Deepslate
NO11

Adds 30 new deepslate blocks!

Mineclone2 Copper
NO11

Adds Copper Ore, blocks and items.

Placeable Buckets for Catching Rainwater
Noodlemire

Allows empty buckets to be placed as nodes in order to collect rainwater.

Ropes
FaceDeer

Adds rope boxes of various lengths and also rope ladders.

Multiple Biome Generator
chaosomnium

230 Pseudorandomly Generated Biomes, Trees, Fruits, Ores, Tools, and Liquids

Falls
Just_Visiting

A Particle-based Waterfalls/Lavafalls Mod

Portal gun
AiTechEye

Portals and stuff

Base Modpack
karlexceed

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

NodeCore Nature
Winter94

Adds many new biomes, plants, and scenery

Better Ice
TheFanne

Modifies ice so that it melts into water when broken, and will be melted by torches

Plastic Box
Starbeamrainbowlabs

Adds a recolourable plastic box. Fork of @cheapie's version with improvements.

Poly Decor
PolySaken

My spin on decorative stuff.

You Can't Touch It Either
Avicennia_g

Simple mod adding lockable storage shelves to Nodecore.

Research N' Duplicate
Noodlemire

Obtain and research enough of a specific item to unlock the ability to infinitely duplicate it.

Ocular Networks
PolySaken

Draw power from the world, and use it to power machines and tools.