The Duel Triangle event is now live, and with it, we get some missions for gems:
-Activate a Spell/Trap Card in Duel Triangle 30 times (300 gems)
-Normal or Special Summon a monster in Duel Triangle 50 times (300 gems)
-Duel in Duel Triangle 30 times (400 gems)

For a total of 1000 gems

Furthermore, by collecting 1500 individual points on each respective group, you can get the following titles:
-Fusion Group: Evolution Intertwined Title
-Synchro Group: Hyperspeed Halo Title
-Link Group: Three-Pronged Union Title