A3 Mania has a good selection of custom quests that have been added to make it useful for new players and also play a part in the progression of the game. You can click on the Quest Title to show more information about the quest and it's objectives.

These are general leveling quests that are available for low level players to repeatedly perform so that they can level up in a short amount of time.

Class based quests are Rebirth and Leveling quests which provide a different quest for each class. You can only take the quest of your respective class. These quests provide decent EXP along with Legends which are items that can be used to craft Rebirth Items.