Crystals. It is always available and unlocks at 6-7 XP.
You need to combine three or more gems of the same color to clear the cells with gold tiles.
Magical Items. It unlocks at 10 XP for Event participants. You need to lower a special item down the playing field. To do this, you need to remove the gems under the item by making combinations with them.
Excavations. It unlocks at 10 XP for Event participants. You need to find and free special items hidden under the playing field tiles. To remove the tiles, match gems on them.