What Yugioh cards are capable of negating activation costs?

the only ones I can think of are:


Spell Economics--you don't have to pay any LP to activate spells


Goblin of Greed--neither player can discard from their hand as a cost





(If I think of any more, I'll edit my post.)

What Yugioh cards are capable of negating activation costs?
spell economic makes u not have to pay lp for spell cards





but thats like the one card that does anything like that.
Reply:I honestly don't know any but Skill Drain negates the effect altogether.
Reply:Yugioh...Oh dear