From the introduction:
Loot Harder: A Book of Treasures brings you hundreds of new magic items for your 13th Age game, including true magic items, consumables, and items for new classes.
Brave adventurers (and GMs) will also find game-changing, campaign-defining iconic relics; “minor” magical treasures that require no attunement; and of course (or should we say, “of curse”), those rare riches that exact a price. Plus: adventure hooks, new item types (scepters, chalices, orbs), lair items, linked thematic item sets, and iconic artifacts!
Think you’ve looted as hard as you can? Get ready to LOOT HARDER!