Progressive Quests are quests that you are able to complete gradually as you progress through Daily, Prime and Genesis Quests.
Each quest has an objective to reach in order to unlock the associated amount of XP rewards.
For instance, the Progressive Quest "Sell 10 NFTs" will reward you once you have sold 10 NFTs.
Once the objective reached, the quest will evolve into "Sell 20 NFTs" for you to have a new objective to reach and unlock more XP rewards.