The Japanese Collector Booster does not include serial numbered cards
At one point, before the Companion errata, this was the literal case
This wording is usually found on punisher effects, so this is probably some kind of burn/edict effect
My favorite three decks: Blue-Red 4-drop spells : This is the base archetype for UR, and is supported quite well Grixis Control: As the name suggests, this is basically just all the good Grixis removal and card draw combined, with some lands for good measure
For formats that care about colour identities like Commander and Brawl, be sure both sides fit entirely within your Commander's identity, otherwise, they are not legal
It makes sense as each deck focuses on a different clan