Legal not just in Vintage, Legacy, and Commander, this is also a straight-to-Modern set, like the two Modern Horizons sets before it
Two dynamite cards in one
In terms of cards, each Doctor Who Commander Deck contains a 100 card, pre-constructed Commander Deck, plus 10 Planechase Cards (which add an extra layer of randomness and special effects to your MTG games, should you choose to use them) and a Collector Booster Sample pack, which contains 2 special alt-frame cards, including 1 Rare or Mythic Rare card
Its a little more expensive but has a very relevant creature type and card advantage
Perhaps an expiring Demonic Pact
You only need these things to trigger off your stuff but it is nice when it is every ones