Manipulate the top of your deck, and go right along with those cards of mana value 4+, you need to really try to avoid value out of Glarb's combined abilities
While you shouldn't expect to connect with it all that often it will act as a Call to the Grave pretty effectively against most players
Target blue players, strip them of counterspells, and create a battlefield where you call the shots
A great example is my Gale, Waterdeep Prodigy/ Raised by Giants deck, where I look to use instant and sorcery pump spells to gain value and take out opponents
I suppose you might think of this list this way: if someone else has them on the battlefield, are you likely to want to get rid of them
Never mind the nuanced MTG origins, what actually is Orzhov Sewers in the first place