The "Elemental Thunder" deck packs big creatures that become more powerful with every move your opponents make. Everyone will wince as you put creature after creature onto the battlefield, each with the potential to single-handedly defeat an opponent in a few turns.
You will want to cast your big creatures early and often. Smokebraider, Rampant Growth, and Search for Tomorrow all give big boosts to your mana production. Use Flamekin Harbinger to search your library for the most threatening creature you can find. You won't believe the look on opponents' faces when they're suddenly staring down the business end of an early Verdant Force or Living Hive!
This deck relies on some important creatures to defeat multiple opponents. Taurean Mauler looks puny at first glance, but against many opponents it becomes very scary very fast. The same goes for Forgotten Ancient, which gets bigger and bigger with each spell cast. With such huge threats, opponents might gang up to stop you early on. Protect yourself by forging an alliance, but if you get the chance to take out an opponent, go for it.
Your planar deck offers support for your huge Elementals. Creature spells cost less on Turri Isle, making it easier to drop big creatures earlier in the game. Tapping a land in the Eloren Wilds produces an extra mana, which is great for casting expensive creature spells. Or you can just pump all that mana into putting +1/+1 counters on Ivy Elemental. On the Isle of Vesuva, creature spells summon two creatures. What could be better than getting two enormous Elementals for the price of one.