The event shop could sell tool visuals for all the skill tools.
For example a flameing effect for the tools.

So it would work in the event shop you could buy the flaming effect for pickaxes for 25 horseshoes and then whenever you use a pickaxe it will have a flaming effect on it. When you equip a tool first there will be a feature area where you pick what effect you want like default or which ever ones you have bought.

Some ideas for effects
Flaming effects to the tools
Glowing effect
Rusty or old look
Dark/evil look(black flames coming off it)  

That should replace the boring old hats