Redstone Activator (previously Lighter) is a new tool. It's basically like flint & steel, but it activates Redstone Dust & other redstone related items and blocks.
And without needing to place blocks or activate levers and buttons.
It activates redstone for 1 tick, but you can hold it to make it last longer. It has unlimited uses so that's not a problem. (Or at least thousands.)
Crafting recipe: Quartz, redstone dust and an iron ingot.