OverTwilight

Adventure and Exploration:

contains many cosmetic features and biomes to the world appealing to people who enjoy variety.

You will also fight challenging monsters from Ice and Fire, and Mowzies Mobs, and Lycanites Mobs.

Notes: Was Intended for server play because of its difficulty, the vast amount of playstyles, although if you want the hardest challenge of your life you can play solo.

Tinkers:

If you like to go the extra mile for variety in your traditional weapons.

The Twilight Forest also contains most of the endgame content but it is very difficult to activate the portal, as you need a Wither Core.

Lycanites Mobs:

A few changes were made so this mod doesn't make anything annoying, although it expands on the variety of enemies you can fight. There will be no Cinders, Reapers or Tremors.

1UP: 

Yeah not exactly a second life but you will have 20 full hearts or 40hp instead of 20hp, to balance this enemies are very strong, but this makes healing to full hp much more challenging.

Progression: The Overworld is home to the most important upgrades such as baubles, but your going to have to conquer the Nether and End, to be able to go to the Twilight Forest. If you want a endgame goal defeat the Ender Chicken Boss, or the Lycanite Bosses. The Twilight Forest and End are the hardest dimensions, your going to need gear that is better than max in vanilla to stand a chance.