Child of Alara and Progenitus just do their own thing, and you build your deck behind them
Being an instant isnt even that interesting here, since the addendum text encourages you to run it out during one of your main phases anyway
Coming in at number nine on this list, we have none other than Dig Through Time
You could also activate a tap ability in response to an attack, tapping a creature to gain some benefit before it blocks
Oath of Ajani, Oath of Jace, Oath of Liliana, and Oath of Teferi: enhance planeswalker efficiency, provide protection, and allow double activations
With one player gaining so much while all others lose resources, it's easy to find yourself in a hole that you can't get out of