Hey there, folks. Ridley here with a neat mod idea inspired by the Ars Magica 1 and 2 mods and Diablo 3.
The main idea of VoidCraft is to control the void and use it to your advantage in battle and otherwise by giving you cool abilities with neat and useful upgrades.
Unfortunately, the only parts of VoidCraft I really have figured out are how you really start it and the abilities. The names are definitely not for certain.
To start off VoidCraft, you would need to jump into the void in the End, maybe with a certain item on you or something. After jumping into the void, you would be sent to a new dimension: The Void Maze. Unable to break the blocks in it, you would find your way through the Void Maze, collecting loot from chests and fighting odd void-dwelling monsters. Eventually, you would find your way to the heart of the Void Maze, where the Void Entity would be. Right-clicking the Void Entity would cause you to be taken back to your spawn point with a server-wide message "[Player123] stared into the Void, and it stared back..."
After that you might have a bar of Void Energy or something and unlock a hotkey to open your Void Powers GUI. The VPGUI would have a web of Void Abilities, most of which grayed out because you're too low of a level.

Void Abilities would include, but would not be limited to such things as:
Void Container: Store items and blocks and anything else you can put in a chest. Items dropped from mobs and blocks destroyed by other Void Abilities would go here or be deleted if the Void Container is full.
Void Duel: Send you and one target to a Void Arena to battle one on one
Void Bubble: A protective shield of Void Energy
Void Aid: Summon a Void-dwelling monster to attack a target once
Void Beam: A beam of Void Energy that sends block targets to the Void Container, and gives players and mobs a wither-like debuff called Fading Light. Players killed by Void Beam or Fading Light would have part of their inventory sent to the caster's Void Container, while items dropped by blocks and mobs who died from Void Beam or Fading Light would do the same.
Void Suffocation: Use solid Void Energy to suffocate targets within 2 blocks of the main target block, 3 blocks high. Players killed in Void Suffocation have part of their inventory sent to the caster's Void Container, while items dropped by blocks and mobs who died from Void Suffocation would do the same.
Call of The Void: A sort of quick portal to the heart of the Void Maze.
Void Blast: A blast of Void Energy. Players killed in Void Blast have part of their inventory sent to the caster's Void Container, while items dropped by blocks and mobs who died from Void Blast would do the same.
Void Punch: Surrounding your hand in Void Energy, you punch a target, giving them the Fading Light debuff. Players killed by Void Punch or Fading Light would have part of their inventory sent to the caster's Void Container, while items dropped by blocks and mobs who died from Void Punch or Fading Light would do the same.
Void Suction: Use Void Energy to pull mobs and blocks toward you.
Void Stomp: Surround your foot with Void Energy and stomp the ground, removing one layer in a seven long, seven wide circle, and doing area of effect damage. Players killed by Void Stomp would have part of their inventory sent to the caster's Void Container, while items dropped by blocks and mobs who died from Void Stomp would do the same.
Void Flight: Use Void Energy to lift yourself into the air, continuously using Void Energy as you use the ability.

That's all I really have for ideas, but I feel that this could have potential to be a pretty good mod. Feel free to tell me what you think. I unfortunately don't have any modding experience, otherwise I would try and do this myself.