I think this element would be very useful. its a powder mayby a liquit and its main property is that it speeds up reaktions and lowers the flame point (and mayby the burning temperature) of burnable elements.
This element would make low-temperature reaktors, better working factories , a hydrogen cell and many other things possible
Most reactions are already fast enough, and adding another particle into the mix prevents the particles that need to touch in order to react from getting close enough to do so. Not sure how to implement this without adding a conditional statement into almost every element in the game, in more than one place :(