The following cards were added to the Banned and Restricted list:
- Mox Opal is banned in the Modern format.
- Oko, Thief of Crowns is banned in the Modern format.
- Mycosynth Lattice is banned in the Modern format.
None of these bannings are particularly shocking, especially not Oko, Thief of Crowns, who had been banned in several other formats throughout Q4 of 2019 (see "Wizards of the Coast Switches To On-Demand Strategy For 'Magic: The Gathering' Format Changes"). Mox Opal's banning was a long time coming as well because it had been contributing to Modern decks with unusually high win-rates for years.
The timing of these bannings coincides with the end of the Throne of Eldraine sales, in which Oko, Thief of Crowns was included as a featured Mythic rare, and the beginning of the Theros Beyond Death sales cycle. These bannings should level the playing field in Modern, and provide in-store OP events a boost going into the new set releases for 2020 (see "Wizards of the Coast Reveals 'Magic: The Gathering' Sets for 2020").