Rosarium

Rosarium is a series of mods added to the base vanilla game with the intention of providing less of a balanced experience, and more of a fun time. It also includes many quality of life expansions as well. 

Full Modlist is as follows

Apotheosis
-A revamp of enchantments and magic

AppleSkin
-Provides on food

Applied Energistics 2
-Most well known for the ME Storage System

Aquaculture 2
-Revamps oceans

Armor Toughness Bar
-Adds a bar of armor toughness above hunger bar

Armory Expansion
-Tinker's Construct addon that allows for further creation of armor via Tinkers Construct

Artifacts
-Allows for the equipment of artifacts with buffs

Astral Sorcery
-Adds a bunch of star based magic

Baubles
-Adds 7 slots to the inventory for new items (Such as artifacts)

Biomes O' Plenty
-Adds lots of new biomes

Blood Magic
-Use blood to cast forbidden magic

Bookshelf
-Helps mods run

BountifulBaubles
-Creates more items for the Baubles slots

Buildcraft
-Known for automation such as farming and quarries 

Clumps
-Clumps EXP orbs to reduce lag

CodeChicken Lib 1.8.+
-Helps mods run

CoFH Core

CoFH World
-Helps the Thermal Modpacks work

Comforts (Forge)
-Adds small quality of life items such as sleeping backs

ConnectedTexturesMod
-Connects Textures

Construct's Armory
--Tinker's Construct addon that allows for the creation of armor via Tinkers Construct

Cooking for Blockheads
-Creates a cook book and allows for autocooking

Cucumber Library
-Helps mods run

Culinary Construct
-Addon mod for Tinkers Construct

Cyclic
-Adds small machines to help you, along with inventory, crafting, and HP upgrades

Dark Utilities
-Adds small machines to help you 

Deep Mob Learning

-Allows for mob resource automation through machines and computers

Deep Mob Learning - Blood Magic Addon
IterationFunk
deepmoblearningbm-1.12.2-1.0.1-universal.jar

Enchantment Descriptions
-Adds a description of enchantments

Food Expansion
-Adds lots of food

Guide-API
-Helps modders create guide books

Hunting Dimension
-A dimension that allows you to hunt certain mobs

Industrial Foregoing
-A mod allowing for certain automations of lots of things

Inventory Pets
-Pets in the inventory that eat stuff and grant buffs

JourneyMap

-Provides a minimap and a mega map along with waypoints

Just Enough Energistics (JEE)

-Allows JEI to check Applied Energetics 

Just Enough Items (JEI)
-Allows you to check crafting recipes for items

Just Enough Resources (JER)
-Allows JEI to display how to get raw resources

Mantle
-Helps mods run

Matter Overdrive: Legacy Edition
-Known for making you into a robot

Mekanism
-Adds machines for new items and automation

Moar Tinkers
-Expands Tinker Construct capabilities

Mystical Agradditions

Mystical Agriculture
-Mystical Agriculture allows for the growth of resources

NuclearCraft: Overhauled

-Allows for the creation of power via nuclear reactors

OMLib
-Helps mods run

Open Modular Turrets
-Allows for the creation of turrets that will defend your base

Patchouli
-Helps mods run

Placebo

-Helps mods run

project-659085
-This is the Essential Mod, which has the key feature of allowing multiplayer games through internet rather then servers

ProjectE
-Most recognized as the mod that allows for energy transmutation

Redstone Flux
-Redstone Flux is part of the Thermal Modpack that switches them from FE to RF

Shadowfacts' Forgelin
-Helps mods run

Skin Layers 3D (Fabric/Forge)
-Makes your skin have 3D layers instead of 2 flat layers

Tesla Core Lib
-Helps other mods work

The Twilight Forest

-The well known dimension that adds a bunch of mobs and bosses

Thermal Cultivation

Thermal Expansion

Thermal Foundation

Thermal Innovation
-Allows for lots of machines to be made

Thermal Tinkering
-Allows for the use of Thermal items to be used in Tinkers Construct

Tinkering with Blood Magic
-Allows for the use of Blood Magic items to be used in Tinkers Construct

Tinkers Construct
-The original Tinker Construct with the ability to make custom weapons with various materials

Tinkers' Complement
-A complement mod meant to addon further items to Tinkers Construct

Tinkers' Tool Leveling
-Instead of having limited modifiers for Tinkers Construct weapons and armor, you can level them up for more. 

Tiny Progressions
-Adds small devices that can help you out in minor ways

Waystones

-Adds stones that can teleport you across the world which are found across the world or be crafted.