Draconis
ElCeejo

Adds advanced Dragons and powerful equipment.

Water Life
Gundul

new mobs for your river and sea water

Biome Lib
VanessaE

The biome spawning and management library.

Ocean
StarNinjas

Adds coral reefs, fish, decorative ocean blocks and much more!

Character Animations
LMD

Animates the character

Alive AI
AiTechEye

Advanced survivor ai mobs (npc, monsters and more)

Item Drop
texmex

This mod adds Minecraft like drop/pick up of items to Minetest.

Beautiful Flowers
1faco

Adds many flowers to MT

PaleoTest
ElCeejo

Adds Prehistoric Fauna and Flora to Minetest Game

Skybox
sofar

Allows changing your sky to unimaginably epic scenes.

Ambience Lite
TenPlus1

Add ambient sounds to the world around you

Multidimensions
AiTechEye

Adds a few dimensions/worlds

Caverealms Lite
Shara

A mod for Minetest to add underground realms.

Regrowing Fruits
philipmi

Fruits on trees from various mods will regrow.

Raining Death
aether123

TNT Rains from the Sky

Regional Weather Bundle
TestificateMods

Not every biome is the same and neither should their weather be. The complete weather bundle for any game.

Auroras
random_geek

Adds auroras (northern/southern lights) at night in cold places.

Mineclone Bubble Columns
j45

Adds whirlpools and upwards bubble columns to Mineclone2/5

Climate API
TestificateMods

A powerful engine for weather presets and visual effects. Requires a weather pack like Regional Weather.

Dynamic Liquid
FaceDeer

Flowing dynamic liquids and ocean-maintenance springs.

Lava Ore Gen
Coder12

Makes the lava turn stone into ore over time.

Visible Sneak
niwla23

A mod to make sneaking visible. The player gets smaller on sneak and the viewpoint is lower.

Placeable Buckets for Catching Rainwater
Noodlemire

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

Minor Redefinitions
Linuxdirk

Changes smaller things that are issues for either Minetest or Minetest Game that are technically fixable but won’t be fixed due to several non-technical reasons.

Farming Flood
AFCM

Makes all plants floodable

NextGen Bedrock
StarNinjas

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

Sounds
AntumDeluge

A set of free sounds & API.

Minetest 2D
AiTechEye

Transforms the minetest world into 2d dimension

Algae
Just_Visiting

Algae mapgen addition to "Minetest Game"

Giant Mushroom/ Mushrooms
Hybrid Dog

Add mushrooms and giant mushrooms.

Bucket lite
daret

Bucket - fork of Minetest Game mod with reduced "bucket" liquid flowing

Weather
theFox

A weather mod for minetest.

Lumberjack
joe7575

The whole tree is dropped when you did the bottom node

Caverealms
HeroOfTheWinds

A mod for Minetest to add underground realms.

Snowdrift
paramat

Light-weight weather mod with snow, rain, and clouds.

NC Steam
Winter94

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

Illumination
mt-mods

Causes players to emit light while holding any luminescent item.

Climatez
runs

A weather mod

Waterfalls
Termos

Adds water erosion, so flowing water forms somewhat more realistic looking waterfalls.

Base Modpack
karlexceed

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