Designed to have a vanilla feeling and be good for new people to get into modded Minecraft, but still be interesting for experienced players. Has Exploration, Magic and a minimal amount of Tech.

Create nice looking houses with ArchitectureCraft, Blockcraftery and Chisel.
Fill these buildings with furniture from Bibliocraft.
New structures and biomes to explore in the Overworld and the Nether.
Venture to other worlds with The Aether, The Erebus and The Twilight Forest.
Farm new crops and animals with Animania and Pam's Harvestcraft.
Create large smelteries and produce a plethora of weapons, tools and armors with Tinker's Construct.
Get around in style with Railcraft and Airships.
Explore magic with Astral Sorcery, Botania and Thaumcraft.
Immersive Engineering is the only tech mod, allowing you to process ores and create quick farms, without losing that Minecraft feel.
Lots of Quality of Life improvements, and other fun things, added by mods like Quark, Iron Chests and Inventory Tweaks.

Modlist:

Waddles (by Girafi)
Just Enough Resources (JER) (by way2muchnoise)
Better Builder's Wands (by Portablejim)
Bed Patch (by Mordenkainen3141)
Hwyla (by TehNut)
JustOwls (by MagicLobster)
CoralReef (by primetoxinz)
Bad Wither No Cookie - Reloaded (by Kreezxil)
Just Enough HarvestCraft (JEHC) (by mrAppleXZ)
Shadowfacts' Forgelin (by shadowfactsmc)
ViesCraft - Airships! (by Viesis_Gaming)
Born in a Barn (by Speiger)
Morpheus (by Quetzi)
JEI Villagers (by Buuz135)
Botania (by Vazkii_)
Ruins (Structure Spawning System) (by AtomicStryker)
More Overlays (by FeldiM245)
Cosmetic Beds (by theillusivec4)
Comforts (by theillusivec4)
Super Sound Muffler (by EdgarAllen)
The Erebus (by vadis365)
Just Enough Pattern Banners (by Lorexe)
Placebo (by Shadows_of_Fire)
Farming for Blockheads (by BlayTheNinth)
Better Advancements (by way2muchnoise)
Forestry (by SirSengir)
MmmMmmMmmMmm (by bonusboni)
Thaumic Inventory Scanning (Thaumcraft Addon) (by BlayTheNinth)
WanionLib (by WanionCane)
Magical Psi (by wiiv)
Binnie's Mods (by Binnie567)
Pam's HarvestCraft (by MatrexsVigil)
Fullscreen Windowed (Borderless) for Minecraft (by hancin)
Waila Harvestability (by squeek502)
AI Improvements (by DarkGuardsman)
Winter Wonder Land (by cam72cam)
FTB Utilities: Backups (by LatvianModder)
The Aether (by GildedGames)
Just a Few Fish (by Tmtravlr)
Phosphor (by jellysquid_)
PlusTiC (by landmaster_phuong0429)
Rope Bridge (by LordCazsius)
BiblioCraft (by JDSinclair)
Block Drops (JEI Addon) (by KidsDontPlay)
Gotta Go Fast (by Thiakil)
Farseek (by delvr)
Chisel (by tterrag1098)
CraftStudio API (by ZeAmateis)
MysticalLib (by EpicSquid319)
Immersive Engineering (by BluSunrize)
Wawla - What Are We Looking At (by DarkhaxDev)
ConnectedTexturesMod (by tterrag1098)
ArchitectureCraft - TridentMC Version (by darkevilmac)
Familiar Fauna (by GlitchfiendMods)
Charm (by svenhjol)
Quark (by Vazkii_)
AutoRegLib (by Vazkii_)
Construct's Armory (by theillusivec4)
Thaumcraft (by Azanor13)
No Recipe Book (by Seneschal_Luwin)
Streams (by delvr)
Mantle (by mDiyo)
UniDict (by WanionCane)
Inventory Tweaks (by Kobata)
Controlling (by Jaredlll08)
Thaumic JEI (by Buuz135)
Cooking for Blockheads (by BlayTheNinth)
Storage Drawers Extras (by jaquadro)
SwingThroughGrass (by exidex)
Bear With Me (by LordCazsius)
Iron Backpacks (by gr8pefish)
Mod Name Tooltip (by mezz)
AppleSkin (by squeek502)
FTB Utilities (by FTB)
Fast Leaf Decay (by olafskiii)
Clarity (by EpicSquid319)
Blockcraftery (by EpicSquid319)
The Twilight Forest (by Benimatic)
Just Enough Items (JEI) (by mezz)
Baubles (by Azanor13)
Iron Chests (by progwml6)
Tinkers Mechworks Fork (by crankysupertoon)
Traverse Legacy (1.12.2) (by ProfessorProspector)
Patchouli (by Vazkii_)
Login Shield (by Glasspelican)
HelpFixer (by matthewprenger)
FTB Library (by FTB)
Diet Hoppers (by RWTema)
LLibrary (by iLexiconn)
Chameleon (by jaquadro)
TipTheScales (by Jaredlll08)
Tinker's JEI (by Possible_triangle)
Tomb Many Graves 2 (by M4thG33k)
Toast Control (by Shadows_of_Fire)
Psi (by Vazkii_)
Mouse Tweaks (by YaLTeR97)
Storage Drawers (by jaquadro)
Chisels & Bits (by AlgorithmX2)
JEI Bees (by bdew)
Railcraft (by CovertJaguar)
Grappling Hook Mod (by yyonne)
Animania (by Purplicious_Cow)
JourneyMap (by techbrew)
Astral Sorcery (by HellFirePvP)
Mystic World (by EpicSquid319)
Roots (by EpicSquid319)
Tinkers Construct (by mDiyo)
Unlimited Chisel Works (by asiekierka)
FoamFix for Minecraft (by asiekierka)

Ruins Structures created by ST753M, Kujaku10 and JordanGreywolf.

Lobster's Private Modpack