There are 4 types of formats in Constructed that have Ranked modes, both in BO1 (Best of 1 match) and BO3 (Best of 3 matches): Standard, Alchemy, Historic and Explorer
Thing is, there is an entire section of the rules regulating interactions with face-down cards
Of these, I actually think Sliver Legion is the best for the deck since it works so well for our Go Wide Combat plans, turning even a modest army into a lethal attack
Cabinet selection is therefore an SKU and packaging decision, not a logo decision
On the other hand, if you were to build an [c]Octopus[/c] deck, you might have a harder time finding cards that make that synergy work
You may play those cards for as long as they remain exiled, and mana of any type can be spent to cast them