Provided you have a way to discard cards, this lets you cheat massive creatures with powerful abilities into play, even cards with clauses that cause them to be shuffled back into your deck when they hit the graveyard (like the MTG Eldrazi titans)
As if this werent enough, thanks to having partner, Rograkh decks can flexibly utilize whatever colors a player may want in their deck
However, another guild has caught my eye, one that I believe is the strongest in the set: Boros mechanic in Guilds of Ravnica , mentor, has been mostly brushed aside as a limited-only afterthought
2018-10-05 Mentor compares the power of the creature with mentor with that of the target creature at two different times: once as the triggered ability is put onto the stack, and once as the triggered ability resolves
Now let's turn to mana rocks: Chromatic Lantern taps for any color and then your lands will tap for all of the colors