The owner of a vanguard card is the player who started the game with it in the command zone. The controller of a face-up vanguard card is its owner.
July 23, 2021 · Adventures in the Forgotten Realms
The owner of a scheme card is the player who started the game with it in the command zone. The controller of a face-up scheme card is its owner.
June 1, 2014 · Conspiracy
Conspiracy cards may have any number of static or triggered abilities. As long as a conspiracy card is face up in the command zone, its static abilities affect the game, and its triggered abilities may trigger.