The most used modes chosen in Commander are likely to be drawing two cards and dealing five damage to target creature, though the artifact destruction is also a nifty option if one of your opponents has a particularly annoying trinket on the board
Valley Floodcaller allows you to give Flash to all noncreature spells, allowing you a bit more freedom with when you play Enchantment, Sorcery, and other cards
they are not Standard-legal
Upon entering the battlefield, Omnath deals an amount of damage to any target equal to the number of Elementals its owner controls
Escape Protocol will be very helpful with Niv-Mizzet Reborn on the battlefield, allowing me to flicker him and get another 10-card flop for just one mana when I cycle another card
There will be some times when you need to cast your Nullify on turn two on absolutely anything your opponent plays, just to avoid falling behind