Necris

Added:

Medieval Decorations

Medieval Entity

Enhanced Spawner

Hopper+

Structory

Structory: Towers

Better Combat
Hopo Better Underwater Ruins

Hopo Better Mineshafts

Enchanting Infuser

Distant Horizon

Sky Villages

Savage Ender Dragon

BuildPaste

Mine Cells

Enhanced Block Entities

Aqua Torches

It felt like there wasn't enough diversity in generated structures with the sky and water origins in those respective areas.
The Spirit mod crashes any game that is multiplayer when viewing recipes in JEI. This is a no go if I want to add server support. So I replaced Spirit with Enhanced Spawners to compromise.
Copper Hopper didn't work so I switched it with Hopper+.
I added Enhanced Block Entities to try an elevate some fps drops in certain dungeons. Hopefully this'll provide a nice boost in performance.
Finally I'd like to talk about Distant Horizon. A must add mod if you love adventure in an open world! This mod add LOD (Level of Detail) that keep performance good and shows a mass view.

Removed:

Copper Hopper

Music Box

Pet Owner

Project: Save the Pets!

Realistic Fire Spread

Some mods felt redundant, did not working, or annoying for players.