100 more NPC Allies, Contacts, Foes, and Merchants for any 5th Edition campaign setting.
New monsters, spells, and magic items
Pre-rolled treasure to reduce DM prep time
300+ Further Adventure(TM) hooks to inspire your game
Allies are heroes that will adventure with the party, who will put their lives on the line for them and seek to help the world become a better place through sacrifice and a focus on the greater good. By adding an ally to your party, you can raise the Challenge Rating of the encounter.
Contacts provide quest hooks, services, and information for the party. They're more likely to help the party if they're being paid. Contacts are unlikely to put their lives on the line for the party, so be careful.
Foes level up when the party levels up, and have the opportunity to return time and again in each tier of play. A minor enemy now could become a major threat later in the game. They're not strictly enemies, though, as it may only be their goals that are at odds with the party. Sometimes they may even be allies early in the game, or contacts providing quest hooks, before they come into their own power later.
Merchants provide materials, quest hooks, services, weapons, and armor for payment. Most of the time the payment is coinage, other times it may be favors or side quests. Prices may vary, you may need to haggle.