The quests system is a good way to gain special rewards, such as keys, tokens, claim blocks and much more. Depending on what type of quest you complete rewards can be more unique.
Quests can be obtained via the /quests command, you may chose to either get a mystery clue scroll or a daily clue scroll. Mystery clue scrolls are 1,395 xp each (1,395 xp equals 30 levels), and daily clue scrolls are $1,000 each, but you can only get a daily clue scroll once a day while you can get mystery clue scrolls as long as you have enough experience.
Once you've obtained a mystery clue scroll right-click the item to either get a Common, Rare, Legendary or Limited clue scroll. Each higher tiered clue scroll gives better rewards than the previous tier (Limited > Legendary, Legendary > Rare, etc.).
Once you've completed all the clues on a quest scroll an inventory opens up with all the rewards inside, either take them one by one or press ESC so all the rewards drop on the ground.
If you have multiple clue scrolls in your inventory with the same clues on them a random clue will get chosen to be completed first.
! If you have multiple clue scrolls with walking, swimming, gliding, or gaining experience in your inventory and one of those clues gets completed, all the other ones will go into a negative number. So it's recommended to only keep one walking, swimming, gliding, or gaining experience clue in your inventory. !
Quests crystals are used to skip the top clue on a clue scroll. Just drop it onto the according clue scroll to skip the top clue. Quest crystals can be obtained from completing clue scrolls or as a crate reward.