Quests
There are many quests in Endless Legend, which when completed, can reward 
Dust, 
Influence, 
Strategic Resources, 
Luxury Resources, Quest Technologies, and many other useful things. Quests vary greatly in length and difficulty. Each faction has its own unique Faction Quest. There are also many short side quests which can be unlocked, for example, by searching ruins or parleying with Minor Faction Villages.
Faction Quests
The Faction Quest is the main quest for each faction, and begins the turn after the settling the first city. Each faction quest will reward powerful faction-unique Quest Technologies, and must be completed to unlock the Temple of the Earth's Core (for the Wonder Victory) as well the Epilogue Quest (for the Quest Victory).
Side Quests
Side quests are quests that consists of only a single chapter, and are separated into two main categories: Ruins and Pacification quests. Ruins quests have a random chance of being triggered anytime a ruin is searched. Pacification quests are given by minor factions after using the Parley action on a village, and will always result in all villages in that region being pacified upon success; these quests require the Language Square technology to trigger, and therefore are unavailable to the Necrophages, or any custom faction with the pitiless trait.
Naval Quests are a special type of side quest that were added to the game with the Tempest expansion. There are two main types of Naval quests, ruins quests and Fortress quests. Naval ruins quests are very similar to the quests received by ruins on land, but are triggered by searching the Sunken Ruins scattered across the ocean. Fortress quests are equivalent to pacification quests in that upon completing the quest given by a fortress, you will gain ownership of said fortress.
Global Quests
Global Quests are a special type of side quest that are available to all players in the game simultaneously. There are two main types of global quests, Competitive and Cooperative. Competitive quests involve some goal that can only be completed by one player, and provides a pretty significant reward upon completion. Cooperative quests start by introducing a negative world effect, then presenting a means to remove said effect that all players may contribute to; upon completion, the world effect is removed, everyone that contributed receives a reward, and the player that contributed the most receives an additional reward.
Droplists
Droplists are used to identify what rewards are given for completing quests. Each quest is assigned a loot table and a number of items to reward. Quests will reward different quantities of items based on which technology age the player's faction is in. Not all items have the same chance of dropping, though drop weights are not represented in all tables. For those that include weights: the larger the weight, the more likely an item is to drop relative to other items.