As an example, the Tier III quest "Skyblock!" requires you to have materials to brew potions and rewards with 30 xp, 2 redstone dust, 2 glowstone dust, and the option for any brewing ingredient.

Tier P: Path quests do not have rewards as they serve as the starting point for themed quests.
Tier I: Gives 5 xp.
Tier II: Gives 15 xp and sometimes loot.
Tier III: Gives 30 xp and loot, 50 xp, or 1 level of xp.