Redirect a spell or ability to another target
With every deck you'll also get 10 Planechase cards that will transport you to your favorite places throughout time and space in the Doctor Who universe
Mirror Gallery is a valuable addition to any deck that relies on legendary creatures, as it allows players to have multiple copies of the same legendary creature on the battlefield without having to sacrifice them due to the legend rule
Generally you want to make sure you have a two or three-color identity for a theme like this, and remember that the majority of your good enablers will be in Grixis colors: Brallin, Skyshark Rider plus Shabraz, the Skyshark Raffine, Scheming Seer Chainer, Nightmare Adept Rielle, the Everwise Soul of Windgrace Amber Gristle OMaul plus Agent of the Shadow Thieves (or Criminal Past) Slogurk, the Overslime Despite their contrarian approach to the Commander metagame, discard decks are capable of some truly disgusting lines and offer a huge range for individual expression
No blue though, so thats a knock against it
Whenever you can, use the strength modifying cards to make smaller characters survive or take out a bigger character