You can get them from trades with Bill(Ishihara) after he appears, and can possibly trigger a new trade if you talk with a specific NPC in each of the Pewter/Fuchsia/Cinnabar Clubs(Rock/Science/Fire)
Tapping for a red/blue and blue/black respectively, you can guess how Grixis is the best color combination
Lets use Lib to tie everything together
You dont get a discount on the creatures you recast so this isnt a reanimation commander, but it exploits cheap threats like Inti, Seneschal of the Sun and Fable of the Mirror-Breaker for a grindy midrange strategy
It forces both players to use T instead of whatever attack was chosen
Examples: Trevas Ruins (taps for green, white, or blue) Darigaazs Caldera (taps for black, red, or green) 5