Here are the lists I want the most:
Unoriginal:
Accelerator's vector powers - well I don't really understand how it works, but what I know is OP
Emiya Shirou's tracing - creating weapons out of nowhere? Works for me!
Emiya Kiritsugu's Time alter - More like an escape skill during fights
Original :
Slayer/Mercy mode - Mercy mode enhance all weapons into non lethal weapons, but only suck Mercy force (a type of energy) and replenish self. Note that it suction rate can be controlled and Mercy force can be used as regeneration to either user or cast it on others. For example getting slashed by Mercy katana won't kill or injure you, but you will only feel energy-less and lose the ability to even move a finger. Slayer mode enhance everything that the user holds into deadly weapons. So even a pillow can break a concrete wall. Victims killed by weapons in Slayer mode will regenerate the user with Slayer force that can revive a dead being.
Judgement - Able to detect Slayer/Mercy force one holds. User will be able to predict movement, mentality and actions by sensing Slayer/Mercy force.
Equilibrium - Ability to switch between Slayer and Mercy mode instantly.