About [I/L Mage] & [ Equipment] : Which Eqs / Set Effect have Skill Cold Down - ? Sec

I know Hats for sure can have cooldown reduction, as well as the Mercedes Character Card.

There's also an Inner Ability line at Unique+ that gives you a small chance (I think 5%?) to ignore cooldowns.

And I/L's Ice Counters affect all bosses. Frozen Orb's just the best way of doing so, and Vellum in general's annoying to stack them on because of the amount of time he spends underground.

Highest chance you can get to ignore cooldowns is 20% at legendary inner ability. It is extremely useful for a lot of classes despite the fact that it doesn't work on hypers.