Tarkir: Dragonstorm and Edge of Eternities also had some really powerful designs, and while they weren't my favorite Limited environments, they definitely added some great cards to Standard (honorable mention, Consult the Star Charts)
From Arabian Nights we've got a signed Serendib Efreet (PL) as well as Khabal Ghoul (GD) and Diamond Valley (PL)
If the ground gets mucked up, it gets around needing the combat step to deal damage
There are any number of brutal combos you can execute here, including using Spine of Ish Sah as removal and damage each turn, or using Scrap Trawlers effect in tandem with Foundry Inspector and Sculpting Steel to infinitely loop artifacts in and out of your graveyard
The mono-colored hybrid mana symbols like the one on Spectral Procession count as 2 towards a cards mana value
Reidane's Shield is valuable to locking down damage and countering targeting effects from everything from Shriekmaw to Swords to Plowshares to Oko, Thief of Crowns unless they spend a mana tithe