This pack aims to improve Minecraft without deviating too awfully far away from the feel of vanilla. A few of the aspects that are improved with this modpack (According to Vers. 1.0.2):

The World Gen:

With Biomes O' Plenty taking the bulk of surface world gen, the swamplands are also given some love with Swamp Expansion, Atmospheric, and Traitor's Better Swamplands.

While 1.13 definitely was a good start to improving the oceans, Upgrade Aquatic and Brine add to it by adding new unique mobs, and even a completely drowned dimension from Brine. Dynamic World helps add some new, neat points of Interest here and there.

The caves underneath the world are overhauled by YUNG's Better Caves & Mineshafts, along with Dungeons+ and Dungeon Crawl to add some interest in the underground.

The Mobs and Animals:

Let's be honest; Minecraft 's animals are boring, and the mobs are all pretty easy to kill.

While Apotheosis, among it's larger additions, adds wickedly powerful boss mobs to the caves, there are a few mods here that add more interesting and unique mobs, such as:

Sully's Mod, Rotten Creatures, Better Animals Plus, and Aquaculture 2 (Which adds many fish mobs).

As of 1.0.3, Wyrmroost is also added, giving several incredible quality dragons, all of which are tameable. The dev team behind this mod has done a phenomenal job designing and creating these dragons, from the animations and textures to the mechanics.

Along with all of this: Naturally Spawning Vex does what it sounds like it does, and Deadly End Phantoms cause Phantoms to spawn rapidly in the End. Herd Mentality makes all animals of a kind run away once you deal damage to just one of them, and Genetic Animals completely overhauls the vanilla animals and adds interesting genetic and behavior mechanics. Spiders 2.0 also revamps spider mechanics so they're more spidery and nope.

Oh yeah, and Infernal Mobs, is, well... A nightmare.

Enchanting, Combat, and Foods:

The previously mentioned Apotheosis massively expands enchanting, adds potion charms, and makes Wandering Traders actually useful by giving them often incredibly powerful weapons, armor, or tools as one of their trades. Spartan Weaponry & Shields does adds, well... Weapons and shields. SwingThroughGrass adds exactly what you think it does. Oh, and now there's a sandbag to beat up if you wanna know how much damage you deal.

As far as food goes, many of the mods here add a couple new consumables themselves, although Food Expansion: Reimagined adds food that actually makes sense, like horse meat, Llama steak, and bacon. Aquaculture 2 also added fish as food, go figure.

(I plan to add Ice and Fire at a later date, possibly once I can make a second modpack similar to this one for 1.16)

Dimensions:

As mentioned before, Brine adds a drowned dimension; though, let's be honest... The vanilla Nether and End is awful.

So, Future Versions is installed to loosely bring the 1.16 update to this 1.15.2 modpack. Along with that, Beyond the Nether Wastes is installed to make the Nether even better. The Bones mod also adds a bunch of skeletal animals into the Nether. With the End, Progressive Bosses is installed to make the Ender Dragon fight more fulfilling to repeat and Grind (As well as the Wither), and the Endergetic Expansion is here to make the End much more interesting to explore.

Creativity:

The mods Decorative Blocks, Fairy Lights, and Create are here to make building and designing mechanics 10x as fun.

Some Miscellaneous mods are Quark, Charm, and Strange, along with Better Burning.

The Campsite

Apotheosis

AppleSkin

Aquaculture 2

Armor Slots in other Inventories

Atmospheric

AtomicStryker's Infernal Mobs

AutoRegLib

Bed Benefits

Better Animals Plus

Better Burning

Better Drowning

Beyond the Nether Wastes

Biomes O' Plenty

Blueprint

Blur

Bones

Bookshelf

Brine

Champions

Charm