Ancient Fantasy

Ancient Fantasy is a groundbreaking expansion featuring new mobs, bosses, loot, and towns. I would classify this primarily as a late-game addon, as the majority of the mobs and bosses you will encounter are incredibly tough. For example, one of the best sets in the game — the Dragonscale Armor is crafted from scales dropped by none other than the Ender Dragon itself.

Credits: Dinolads

Towns

The addon introduces Towns, a new category of generated structures. Towns act as specialized villages designed specifically for this mod. They house several new types of villagers, each with unique names and appearances. You can even hire Human Knights for service using Emeralds; simply drop armor and weapons on the ground to equip them. In my experience, towns often generate beside or even inside existing villages, causing buildings to overlap. However, they also appear in open plains, so it is fair to say the world feels much denser with structures.

Bosses

Summoning bosses often requires a specific series of steps. For instance, to summon the Necropolosis, you must first kill a Weaver mob to obtain a Deactivated Totem. Then, you must kill a Catastrophe while holding the totem in your offhand. Finally, use the Activated Totem to summon the boss. For more complex rituals, you can look up the full requirements on the official Wiki.