With only a little more than a stack of mods, this forge modpack is centered around The Origins Mod, exploration, and cooperation. It has 33 Origins to choose from, and lots of dungeons to explore / bosses to fight.

It also has a lot of other mods to keep you entertained including:

Lots of biome mods for the overworld, nether, and the end (OTBYG, Better Nether/End, and more)
Lots of mythical creatures to battle and tame (Fire & Ice, Astemir's Forestcraft, and more)
4 dimensions mods (Atum 2, Blue Skies, Tropicraft, and The Abyss Ch. 2),
3 tech mods (Create, Immersive Engineering, and Applied Energistics 2),

Some other notable mods in this modpack include:

Capsule - for taking your bases with you on the go
Lightmans Currency - for trading with your friends
Gravestones - for keeping your stuff from despawning after death
Waystones - for teleporting
Chisels and bits - for building immaculate structures
Witchery: rewitched - for being a witch
SecretRoomsMod - for hiding your valuables from your less trustworthy friends
Total Darkness, and Dynamic Surroundings - for a more immersive experience
Morpheus - when your lazy friends don't want to sleep.

We made this modpack in a day for a small Discord group with less than thirty members, so don't expect it to be completely flawless.

Here's a list of all the mods and their creators:

I made the name of this origins modpack very long ;)